Launch Conditions
Use cautionLaunch with caution — limited daylight.
- Advisories
- None active
- Daylight
- Past sunset (8:40 PM)
Live from the National Weather Service, USGS, and NOAA. A guide, not a substitute for official forecasts and your own judgment.
Launch Light & Moon — August 1
local timeWaning Gibbous (86% illuminated). Good fishing outlook — the moon is approaching a major phase.
Location
Quick Facts: Grant Marsh
| Location | Montana |
|---|---|
| Waterbody | Bighorn River |
| Access Type | Public - Free |
| Coordinates | 45.842107, -107.594366 |
| Hours | Check on site |
| County | Big Horn |
Grant Marsh is a public boat launch providing access to Bighorn River in Montana at coordinates 45.84211, -107.59437. Data published by Montana Fish, Wildlife and Parks (MT FWP).
Grant Marsh is a public boat launch on Bighorn River in Big Horn County, Montana. As a public launch it is open to all boaters; state- and county-run ramps like this are typically free or charge only a modest day-use fee. This page shows sunrise, sunset, and moon-phase times for the launch, updated automatically. There are 5 other mapped boat ramps within about 15 miles if conditions here aren't right.
Related: boat launch in Big Horn • fishing access on Bighorn River • Montana boat launch
Explore more boat launches across Montana
Buying or selling a boat?
Decode any boat's HIN free, or run a full $9.99 history report before you buy.
Frequently Asked Questions About Grant Marsh
Is Grant Marsh free to use?
Yes, Grant Marsh is a public boat launch with free access in Montana.
What water does Grant Marsh access?
Grant Marsh provides boat launch access to Bighorn River in Montana.
How do I get to Grant Marsh?
Grant Marsh is located at coordinates 45.842107, -107.594366 in Montana. Use the "Get Directions" buttons on this page to navigate with Google Maps or Apple Maps.
Get Directions
Navigate directly to this boat launch using your preferred mapping service:
Alternative Boat Launches Nearby
The area surrounding Grant Marsh includes 5 other public boat ramps within 14.0 mi, giving boaters flexibility in choosing their access point.