Boxelder Creek flows generally from north to south, draining an approximately 260-square-mile watershed that extends from southern Wyoming to the creek’s confluence with the Cache la Poudre River three miles southeast of Fort Collins, Colorado.
Flowing from the northwest, Boxelder Creek is joined in the eastern part of the basin by several southerly flowing tributaries: Sand Creek, Rawhide Creek, Coal Creek, and Indian Creek.
These creeks form a common flood plain that continues south to the Cache la Poudre River.
The watershed is about 32 miles long and 8 miles wide. It includes parts of Larimer and Weld counties in Colorado and parts of Albany and Laramie counties in Wyoming.
Elevations in the watershed range from about 7,720’ in Wyoming to 4,860’ where Boxelder Creek joins the Cache la Poudre River.
The climate in the watershed is semi-arid, with uneven distribution of precipitation. High intensity, short duration thunderstorms that can cause damaging runoff occur once every two to three years, generally from April to October.
The lower part of the Boxelder Watershed includes irrigated and non-irrigated agricultural land as well urbanized areas.
With increased urbanization over the last 40 years, the amount of residential and public infrastructure has greatly increased.
Interstate Highway 25, U.S. Highway 87, State Highways 1 and 14, numerous county roads, and a railroad cross the watershed area.
Parts of unincorporated Larimer County, the towns of Wellington and Timnath, and southeast Fort Collins are located in the watershed. They are also located within the Federal Emergency Management Agency (FEMA) 100-year floodplain for Boxelder Creek.