Denver Colfax Marathon 2026: Route Map, Course Guide & FAQ

The Denver Colfax Marathon ran on Sunday, May 17, 2026, on courses through Denver and Lakewood, according to the official course map. The race is over, so this page now serves as a reference for the course, the race family and the next race weekend. The Marathon Course Overview describes the event as Denver, Colorado's only marathon, alongside a half marathon and an urban 10 miler. Every date and detail below comes from the organizer's pages, and anything those pages do not state has been removed from this revision.

The official course map shows the Denver Colfax Marathon 2026 courses running through Denver and Lakewood. It is the starting point for anyone checking the colfax marathon 2026 route before choosing a distance.

The Marathon Course Overview page carries three things:

• maps of the course
• a written course description
• a photo tour

The description breaks the course into 5 sections marked by color on the first map. A linked elevation map sits on the same page. The organizer's maps are the reference for planning, and they are the pages to open first when the route matters to your day.

The organizer divides the marathon into 5 color-coded sections, and that division is the cleanest way to walk the course. Open the first map on the overview page and follow the colors in order. Each color marks one section of the route. The full course map shows the same route as a whole, running through Denver and Lakewood.

A workable order for using the two pages together:

1. Start with the full map to see how the route sits across Denver and Lakewood.
2. Switch to the overview page and read the description section by section, matching each passage to its color.
3. Open the linked elevation map and compare it with the colors, so the climbs and descents line up with the sections.
4. Browse the photo tour for a look at the streets.

Specific mile markers, turnarounds and landmarks from the earlier version of this post are no longer listed here, because the official map pages are the place that states them. Each shorter race has its own guide on this site: the Half Marathon guide, the 10 Miler guide, the 5K guide and the Relay guide.

Elevation is a fact worth planning around, and the organizer links an elevation map from the Marathon Course Overview. Anyone searching for the colfax marathon elevation profile should open that linked map directly. It sits beside the five color-marked sections, so each stretch of the route can be read against its climbing and descending.

The earlier version of this page gave a range of feet, a total ascent and a percentage for oxygen at altitude. None of those figures appears in the organizer's pages listed here, so they have been dropped. Read the map yourself, set an easy effort for the opening miles, and let the organizer's profile, not a rounded number, shape your pacing.

For race weekend, the official course map states that traffic traveling north and south on I-25 will be open. That matters for anyone driving in from either direction, since the interstate stays available while the courses run through Denver and Lakewood.

Start times, packet pickup hours, parking, aid stations and cutoffs from the earlier version have been removed, since no listed source states them for this revision. The Registration page is the organizer's main page for entries, and it is the place to look before any race weekend.

A short outing done early beats a long one done late, and that holds for spectators too. Arrive before the streets fill, because the crowd along a route gets thicker as the morning goes on. Check the forecast the night before and again at dawn. Carry water, sun protection and a layer, and confirm with the organizer what is provided on the course.

The Registration page lists individual registration for four races: the Marathon, the Half Marathon, the Urban 10 Miler and the Colfax 5K. Each has its own guide on this site:

• Half Marathon: Denver Colfax Half Marathon 2026 is the guide for runners comparing the denver colfax half marathon 2026 course with the full.
• 10 Miler: the 10 Miler guide covers the middle distance.
• 5K: the 5K guide covers the shortest race.
• Relay: the Relay guide covers team entries.

Relay registration is listed separately on the Registration page, with the line "Register now to save money for your team." A Multiple Registrations option is also listed, which is the place to look when entering a group. Race details sit on the Marathon page and the Half Marathon page.

Fees from the earlier version have been removed. The pages above do not state them in the material this revision draws on, so check the Registration page for current pricing.

The site header on the Registration page shows May 15-16, 2027, which is the next race weekend. The earlier dates given for 2027 in this post's older text have been replaced with that header.

Planning ahead can use the same pages that served the 2026 race: the course map for the route, the overview page for the five color sections and the elevation map, and the Registration page for open entries and the Multiple Registrations option.

The Denver Colfax Marathon 2027 guide covers that weekend in full. Anyone looking at a different Colorado marathon can read the Boulderthon 2026 course guide.

Is the Denver Colfax Marathon a Boston qualifier? None of the listed organizer pages in this revision states qualifying status, so the earlier claim was removed. The Marathon page holds the race details to check before entering.

What are the 2026 Colfax Marathon start times by distance? The 2026 race ran on Sunday, May 17, per the course map. The earlier start times were removed because no listed source states them. The Half Marathon page and the Registration page are the organizer's pages to check for race details.

How much does altitude slow you on the Colfax course? No listed source gives a slowdown figure. The organizer's elevation map, linked from the course overview, shows the climbing. Read it before race week, start with an easy effort and drink water through the morning.

Where is packet pickup and when does it close? The earlier pickup location and hours were removed because no listed source states them. The Registration page is the organizer's page to check before race weekend.

Can you switch race distances after registering for Colfax? Transfer rules and fees from the earlier version were removed for the same reason. Start from the Registration page, which also lists the Multiple Registrations option.

Updated 2026-10-12: marked the 2026 race as run, removed figures the official site does not state, and added the May 15-16, 2027 header.