A village on the northeastern boundary of North Lanarkshire Council Area, Castlecary is situated to the west of the A80 road and south of the Forth and Clyde Canal, 2½ miles (4 km) northeast of Cumbernauld. The village once extended into the modern Falkirk Council Area, including what is now the settlement of Allandale, and the names of the 15th-century Castle Cary, Castlecary Woods, Castlecary schoolhouse and Castlecary Mill Farm (all now in Falkirk) reflect this. A Roman fort on the Antonine Wall was excavated nearby in 1902.
There were once two brickworks here, both established in the 19th century. One closed in 1968, while the other continued until the 1980s. Cumbernauld Airport lies a mile (1.5 km) to the west southwest.