Leyner is an unincorporated community and a census-designated place (CDP) located in and governed by Boulder County, Colorado, United States.

The population of the Leyner CDP was 40 at the United States Census 2020.

[3] The Lafayette post office (Zip Code 80026) serves the area.

[4] Leyner is located in eastern Boulder County along the west side of U.S. Route 287, 4 miles (6 km) north of Lafayette.

[5] Leyner does not appear on topographic maps until 1951, and it was adjacent to a siding, indicating that it was probably a railway station at some point in history.