Route 866 may refer to:
| Preceded by 865 | Lists of highways 866 | Succeeded by 867 |
Pennsylvania Route 866 is a 22.4-mile-long (36.0 km) state highway located in Bedford and Blair Counties in central Pennsylvania. The southern terminus is at PA 36 in Woodbury. The northern terminus is at U.S. Route 22 in Frankstown Township.
Route 866 is a north-south regional highway in northern Israel. It begins at Hananya junction with Highway 85 in the south and ends at Meron junction with Highway 89 in the north.
King's Highway 109, or Highway 109, is a former provincial highway in Ontario. It was used on two separate, unrelated routes during the 1950s and 1960s:
Secondary Highway 500, commonly referred to as Highway 500, was a secondary highway in the Canadian province of Ontario which was first designated in 1956. Its route was renumbered in 1964, becoming:
Secondary Highway 514, commonly referred to as Highway 514, was a secondary highway in the Canadian province of Ontario. It was used on two separate routes from the 1950s to the 1990s:
