HalfRuns
Big Sky Marathon

Big Sky Marathon

Big Sky Marathon and Half Marathon offers a flat, fast course through Montana's scenic Madison Valley.

Race Date

Jul 12, 2026

Location

Ennis, MT

Solid Pick42

Quick facts

Date
Sunday, July 12, 2026
Location
Ennis, Montana
Distance
Half marathon (13.1 mi) + 26.2M
Course
Loop Course
Terrain
Road
USATF certified
Not listed
Finishers on record
486

Highlights

Good For

PR FriendlyDestination Worthy

Atmosphere

Local CommunityWell Organized

Course

Fast Flat

The Experience

The Big Sky Marathon and Half Marathon winds through Montana's picturesque Madison Valley, offering a predominantly flat and fast course. This race, first run in 2003 and now in its 13th edition, is known for its potential for personal bests, with a typical winning time around 96 minutes for the half marathon.

Runners from approximately 11 states have participated in recent years, drawn to the stunning natural beauty of the area. While the race has a growing field, its repeat-runner loyalty is low, suggesting a fresh experience for each participant.

The event takes place in Ennis, Montana, with typical race-day temperatures ranging from the mid-50s to the mid-80s Fahrenheit, making for comfortable running conditions.

Race-provided description

The Big Sky Marathon is the result of our success with the Madison Marathon. We held our Inaugural race in 2015 to appease marathoners from around the world who were screaming for a double (both full and half) in Montana. To non-marathoners, this is completely counter-intuitive. Afterall, why would you host a second marathon immediately after one of the most difficult marathons in America? To the likes of Marathon Maniacs and other running groups, it makes perfect sense. Why run just one marathon over a weekend when you can run two? Why not earn Four Stars as a Marathon Maniac over the course of 48 hours vs. possibly earning just one star and only if all your other stars line up?​ We couldn’t answer the why not questions other than to say, ‘Yeah, why the hell not?’ We have a new route (started in 2020).  It's still one hell of a downhill.  Give or take it has a net drop of 3,600 feet.  Turns out, it’s the Second Longest Downhill Road Marathon on Planet Earth, or at least in the top five.  The new route will once again start up on the Gravelly Range Road. The full marathon will start at approximately Mile 17 of the Madison Marathon route. Then, runners head downhill to the Madison Valley floor. Once on the valley floor, runners will no longer run along Varney Road. Instead, they will turn right at the T-junction, cross Varney Bridge over the Madison river, and run out to US Highway 287. That will be the turn-around point. Runners return to the Madison River and finish at Varney Bridge.  So for full marathoners, it will be about 22 miles out and four miles back. For Big Sky Half Marathoners, the starting line will be still up on top but not quite as high as before. It will be around five miles further down the route from the Big Sky Marathon starting line. It will then be a straight 13.1 mile shot to Varney Bridge. None to little traffic. Only a mile or so of pavement instead of more than 10 miles of pavement. And, the race ends on the tranquil waters of the Madison River, not a town park.  A good means to describe the route in terms of its challenges and level of difficulty is to break it down into three sections. Section One – This is from the starting line to the point on the route where the significant downhill begins. The starting line is at approximately 8,500 to 8,700 feet above sea level. The full marathon start is at about Mile 17 of the Madison Marathon. The half marathon start is about 1.5 miles from the intersection of Road 292 and 290. The runners will not drop in elevation too significantly over the first five to eight miles (depending on which race you’re running). There are few or no uphills on this section of the route. It is essentially flat and on top of the Gravelly Range though everything is trending downhill. This entire section is within the Beaverhead Deerlodge National Forest. As runners get close to the border of the National Forest, there will be long, gradual downhills of two to three miles in length crossing enormous bowls and meadows, but they will not necessarily be quad burners. Section Two – This is the quad burner section. It begins almost immediately after runners leave the National Forest. Runners will cross a cattle guard gate and then the next several miles will be a quite steep downhill. This is a series of switch backs that drop the runner from 8,500 feet to 6,000 feet in a relatively short distance. The “official end” of this section is when the road hits a t-junction after going through most of the Bar 7 ranch. The estimated distance is about seven miles. Section Three – This section is a flat area that gradually declines in elevation as it gets close to the Madison River. The lower part of the Bar 7 Ranch is approximately 6,000 feet and Ennis and the Madison River is at about 5,000 feet. The first few miles will be on gravel road, but eventually the runners hit pavement near the Ennis Fish Hatchery turn-off. Once pavement is hit, runners are quite close to Varney Bridge and the Madison River (the finish line).   When runners reach a T-junction, they turn right to Varney Bridge. The half marathon runners cross the bridge and run into the Varney Bridge Fishing Access to the finish line. The full marathoners continue on this road out to Highway 287 which is about four miles away. This section is entirely on gravel road and crosses an enormous open space area with fantastic views of both the Madison and Gravelly Range. At the highway, runners turn around and run back to Varney Bridge and the finish line. That is how you run one of the longest downhill road marathons on Planet Earth!

Logistics

Race Day

Sunday, July 12, 2026

Start Time

9:00 AM

Giveaway

T-Shirt

Start Location

Varney Bridge Fishing Access Site, Ennis, MT, 59729

Directions

Course Info

Course Type

Loop Course

Terrain

road

Scenery

Rural

Surface

Paved

Difficulty

Ultra-Flat

Net Drop/km

0 m (Flat)

Separation

0.0%

Also Offers

26.2M

Quality Score

Solid Pick42
Methodology
Heritage20/20

13 years running

Size8/15

~32 finishers a year

Momentum3/5

small race — neutral

Loyalty0/20

0% returning runners

Course & details6/15

3 timing sources · 8 photos

National draw6/10

runners from 11 states

Front-pack speed0/5

winner 1:36:07

Weather0/10

typical high 84°F

Race Day Weather

5-year historical avg

Start (Low)

57°

Afternoon (High)

84°

Hot conditions — adjust pace expectations, prioritize hydration

0.0"

Precipitation

9 mph

Wind

44%

Humidity

Historical Finish Times

How 486 finishers actually crossed the line across 13 years.

Most recent

2025

Total finishers

486

Median time

2:23:11

Latest turnout

32

States

29

10%
25%
75%
90%
1:10p50 median ≈ 2:055:05

Turnout by year

20172025

'17'18'19'20'21'22'24'25
See full results

Hover the histogram to inspect specific finish times.

Race Photos

Frequently asked

When is the Big Sky Marathon?

The Big Sky Marathon is held on Sunday, July 12, 2026, starting at 9:00 AM.

Where does the Big Sky Marathon take place?

It takes place in Ennis, Montana.

What distances does the Big Sky Marathon offer?

The half marathon (13.1 miles), plus 26.2M.

Is the Big Sky Marathon course flat and good for a PR?

The Big Sky Marathon is a ultra-flat, loop course course.

How many people run the Big Sky Marathon?

HalfRuns has finish records for 486 runners who have completed the Big Sky Marathon.

HalfRuns editorial — independent, no paid placement.

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