Run and Write | Jeremy Criddle

C and O Canal 100 Race Guide

The C&O Canal 100 takes place each year during the last weekend of April in Maryland, offering runners one of the fastest and most accessible century courses in the country. Held along the historic Chesapeake and Ohio Canal towpath near the Potomac River, this race attracts both first-time 100-milers seeking a runnable course and experienced ultrarunners chasing personal records. The race starts at 7:00 AM on Saturday and gives participants a generous 30-hour time limit to complete the distance, with finishers crossing the line by 1:00 PM on Sunday. The combination of minimal elevation change, temperate spring weather, and well-supported aid stations makes this event ideal for anyone ready to tackle the demanding 100-mile distance in a scenic setting near the Appalachian Mountains.

Race Date and Registration

The C&O Canal 100 is scheduled for the final weekend of April each year, with the 2026 edition taking place April 25-26. Registration opens on January 1st at 10:00 AM EST through Ultrasignup, with a non-refundable entry fee of $230 and a cap of 250 runners. The race has historically not sold out, but organizers maintain a public waitlist system if the event reaches capacity. Runners accepted from the waitlist must confirm their spot within 48 hours or the entry passes to the next person in line. Registration closes approximately one week before race day, with absolutely no late entries permitted due to logistical requirements related to the National Park Service permit.

Qualification and Entry Process

The C&O Canal 100 operates on a first-come, first-served registration basis with no qualifying standards required to enter. Runners do not need previous 100-mile finishes or lottery selection to secure a spot, making this race particularly appealing for those attempting their first century distance. The straightforward registration process through Ultrasignup opens exactly at 10:00 AM EST on January 1st each year, and interested runners should be ready at that time to guarantee entry. All finishers under the 30-hour cutoff earn Western States Endurance Run qualifying status, adding extra incentive for runners working toward that prestigious event. The accessible entry requirements combined with WSER qualification make this race a strategic choice for ultrarunners building their racing resume.

Course Challenges

While the C&O Canal 100 is often described as one of the easier 100-mile races due to its flat profile, the course presents unique challenges that should not be underestimated. The packed dirt towpath contains small gravel rocks that gradually wear on feet over the full distance, with many runners reporting that these rocks seem to multiply as the miles accumulate. The surface can feel deceptively hard on the body, and the mental challenge of running a mostly straight path for 100 miles tests focus and determination in ways that varied mountain terrain does not. Nighttime running along the canal requires navigation of a narrow path with limited visibility, though the straightforward course layout reduces the risk of getting lost. Weather in late April can range from pleasant mid-60s temperatures to cold rain and overnight lows in the 40s, requiring runners to prepare for multiple conditions during their 24-30 hour journey.

Course Format

The race follows a multi-loop format starting and finishing at Camp Manidokan near Knoxville, Maryland. Runners complete one approximately 40-mile loop, followed by two roughly 30-mile loops, covering almost the entire distance on the C&O Canal towpath between Antietam and Brunswick. The first loop includes an out-and-back section to the North Turnaround, adding variety to the initial miles, while loops two and three follow identical routes without this extension. Runners encounter the same aid stations multiple times throughout the race, with some stations appearing as many as six times depending on the loop. The course runs between mile markers 44.6 and 69.4 on the historic canal, with runners heading northwest toward Cumberland or southeast toward Washington D.C. depending on their position in each loop.

Elevation Profile

The C&O Canal 100 features minimal elevation change, making it one of the flattest century courses available to ultrarunners. The course is essentially pancake-flat along the canal itself, with the only notable climb being the short trail section connecting the towpath to Camp Manidokan, which runners must ascend at the end of each loop. This transition from canal to camp involves approximately 260 feet of elevation gain compressed into about half a mile, creating a brief but noticeable climb after long stretches of flat running. Total elevation gain for the entire 100 miles remains under 500 feet, a stark contrast to mountain hundreds that often feature 15,000-20,000 feet of climbing. The lack of significant elevation change means runners can maintain consistent pacing throughout the race, though the repetitive flat terrain places constant stress on the same muscle groups without the variation that hills provide.

Terrain Breakdown

The course consists of approximately 98 percent packed dirt and gravel towpath surface, with the remaining 2 percent being single-track trail sections connecting Camp Manidokan to the canal. The towpath itself is a wide, relatively smooth surface composed of packed dirt mixed with small gravel rocks that create a firm but gradually punishing running base. Runners can expect about 60 percent of the course to be shaded by tree cover, with frequent brief stretches of sunlight and only a few sections of prolonged sun exposure along the open canal. The trail sections connecting to Manidokan feature typical forest path characteristics with roots and natural obstacles, though these segments are short and well-marked with orange flagging and reflective tape. The consistent surface throughout most of the race allows for steady forward progress but offers little variation, and the small rocks embedded in the towpath have a reputation for finding their way into shoes despite best efforts to keep them out.

Time Limit and Cutoffs

The C&O Canal 100 enforces a 30-hour time limit from the 7:00 AM Saturday start, meaning runners must cross the finish line by 1:00 PM on Sunday to receive an official finish time and belt buckle. The race features three critical intermediate cutoffs that runners must meet to continue on the course. Runners must depart Manidokan aid station at mile 69.2 by 3:45 AM Sunday morning, leave Dargan Bend at mile 80.4 by 6:45 AM, and exit Brunswick at mile 90.4 by 9:45 AM. Aid stations open for the fastest runners and remain staffed until all remaining runners pass through or the cutoff time is reached, based on an 18-minute-per-mile maximum pace. These cutoffs are strictly enforced to ensure runner safety and to meet permit requirements with the National Park Service. Distance between aid stations ranges from 1.4 to 6.9 miles, with drop bag access available at Brunswick and Manidokan, allowing runners to adjust their gear and nutrition strategy as conditions and physical needs change throughout the long day and night.

Aid Stations and Support

The C&O Canal 100 provides runners with 11 well-stocked aid stations spaced between 1.4 and 6.9 miles apart along the course, ensuring frequent access to food, fluids, and medical support throughout the race. Due to the multi-loop format, some aid stations appear multiple times, with runners passing through certain locations as many as six times during their 100-mile journey. Brunswick and Camp Manidokan serve as the primary drop bag locations where runners can access personal gear, clothing changes, and specialized nutrition items they’ve prepared in advance. Crew members have vehicle access at Camp Manidokan (the start/finish area), Brunswick at mile 90.4, and limited access at Dargan Bend at mile 80.4, though parking restrictions apply at certain locations. All aid stations stock standard ultrarunning fare including water, sports drinks, salty snacks, sweet options, fruit, sandwiches, and hot soup during overnight hours. The aid station volunteers remain committed to helping every runner reach their goals, creating a supportive atmosphere that many participants describe as one of the race’s standout features.

Mandatory Gear Requirements

The C&O Canal 100 requires all runners to carry a headlamp or flashlight with fresh batteries, as participants will be running through at least one full night on the towpath. A cell phone must be carried at all times for emergency communication, which is particularly important given the remote sections of the canal where immediate aid station access is not available. Runners must also have a whistle for signaling distress if needed, along with a small first aid kit containing basic supplies for treating blisters and minor injuries. The race strongly recommends bringing extra warm layers and rain gear given the unpredictable nature of late April weather in Maryland, where overnight temperatures can drop into the 40s and rain showers may develop. While not mandatory, race organizers suggest runners carry their own hydration system or bottles between aid stations, as the maximum spacing of 6.9 miles could leave some participants running low on fluids during warmer conditions. The gear requirements prioritize safety without creating an excessive burden, reflecting the relatively accessible nature of the towpath course compared to more remote mountain ultras.

Crew and Pacing Support

The C&O Canal 100 allows crew support at specific vehicle-accessible aid stations, with the primary crewing locations being Camp Manidokan (start/finish), Brunswick at mile 90.4, and Dargan Bend at mile 80.4. Pacers are permitted to join runners at the Brunswick aid station starting at mile 90.4, meaning runners complete the first 90 miles solo before receiving the benefit of a companion for the final 10-mile push to the finish. Crew members must park in designated areas and cannot access other sections of the canal towpath by vehicle, as the National Park Service strictly controls vehicle traffic on the historic trail. The race provides clear instructions about parking locations and access times, with crews needing to plan their movements carefully given the multi-loop format that brings runners back to Manidokan multiple times. Runners without crew support can still succeed at this race, as the frequent aid station spacing and comprehensive support from volunteers provides everything needed for a successful finish. The pacer restriction until mile 90 ensures all participants tackle the bulk of the challenge independently while still offering companionship during the final miles when fatigue peaks.

Navigation and Course Marking

The C&O Canal 100 uses orange flagging and reflective tape to mark the course, with markers placed frequently enough that runners should always be able to see the next flag ahead. The straightforward nature of the towpath makes navigation relatively simple, as runners spend the vast majority of the race following a wide, obvious trail with limited opportunities for wrong turns. The most critical navigation points occur at the transitions between the canal towpath and the Camp Manidokan trail sections, where race markers guide runners off the flat canal and onto the short forest path leading to the aid station. During nighttime hours, the reflective tape becomes essential for keeping runners on track, though the narrow towpath naturally funnels participants in the correct direction. GPS devices or watches are not required for this race, though many runners choose to carry them for tracking mileage and pace throughout the event. The race provides detailed course descriptions and maps during the pre-race briefing, ensuring all participants understand the loop structure and turnaround points before the 7:00 AM start.

Historical Finish Rates

The C&O Canal 100 maintains one of the higher finish rates among 100-mile ultramarathons, with approximately 75-80 percent of starters completing the full distance within the 30-hour cutoff. The flat profile, runnable terrain, and generous time limit contribute to the strong completion percentage, making this race a popular choice for first-time 100-milers seeking a high probability of earning their inaugural buckle. The 2025 edition saw 169 finishers out of approximately 210 starters, demonstrating the race’s accessibility while still presenting enough challenge to DNF runners who underestimate the demands of the distance. Weather conditions significantly impact finish rates from year to year, with cold rain and wind creating more difficult editions that test even experienced ultrarunners. The consistent finish rates over the race’s history reflect the well-organized support system, frequent aid stations, and straightforward course logistics that allow runners to focus on forward progress rather than navigation or survival. These statistics make the C&O Canal 100 an excellent proving ground for runners ready to step up from 50-mile distances while building confidence for more technical mountain hundreds.

Special Features and Awards

The C&O Canal 100 runs along one of America’s most historically significant waterways, the Chesapeake and Ohio Canal, which served as a critical transportation route in the 1800s connecting Washington D.C. to Cumberland, Maryland. All finishers under 30 hours receive a distinctive belt buckle commemorating their achievement, along with Western States Endurance Run qualifying status that opens doors to one of ultrarunning’s most prestigious events. The race takes place entirely within the C&O Canal National Historical Park, meaning runners traverse protected lands maintained by the National Park Service while experiencing the same path used by canal workers and mule teams nearly two centuries ago. The course passes through areas rich in Civil War history, particularly near Antietam, adding a unique educational element to the physical challenge. Race organizers maintain strong relationships with the National Park Service and local communities, ensuring the event operates smoothly while respecting the historical and environmental significance of the canal corridor. The combination of flat, fast terrain with guaranteed WSER qualifying makes this race particularly valuable for runners building their ultramarathon resume and working toward bucket list events.

Course Records

The men’s course record for the C&O Canal 100 stands at 13 hours, 32 minutes, and 17 seconds, set by Andrew Snope in 2024, showcasing the remarkable speed possible on this flat, runnable towpath. The women’s course record is 14 hours, 35 minutes, and 47 seconds, held by Bailey Kowalczyk from 2024, demonstrating elite-level performance on a course that rewards consistent pacing and efficient running. These record times reflect the race’s reputation as one of the fastest 100-mile courses in the country, with the minimal elevation change allowing talented runners to maintain sub-9-minute-per-mile averages for the entire distance. The relatively recent record dates indicate the race continues to attract competitive fields alongside first-time century runners. Both records were set during the 2024 edition, suggesting favorable conditions and strong competition that pushed the winning runners to exceptional performances. The fast times achievable at C&O Canal 100 make it attractive for experienced ultrarunners chasing personal bests and age-group records in addition to those simply seeking their first 100-mile finish.

Race Contact Information

The official race website for the C&O Canal 100 is located at cocanal100.com, where runners can find comprehensive course information, aid station details, and race updates throughout the year. Registration opens January 1st at 10:00 AM EST through UltraSignup at ultrasignup.com/register.aspx?did=128105, with the 2026 race scheduled for April 25-26. The race is organized by Pandemic Racing LLC and directed by Joe Clapper, who maintains communication with participants through the official website and email updates leading up to race day. Runners can contact race management through the website’s contact form for specific questions about registration, course logistics, or volunteer opportunities. The race maintains an active presence on social media and ultrarunning forums where past participants share experiences and advice for those preparing for their first attempt at the course. All official race communications, including the detailed runner information packet, course maps, and final instructions, are distributed through the website in the weeks leading up to the event.