 When NY 324 was assigned c. 1933, it began at NY 384 (River Road; now NY 266) in the town of Tonawanda and followed Sheridan Drive eastward to NY 5 in the town of Clarence. By 1935, what is now NY 324 between Niagara Falls and Tonawanda via Grand Island was designated as NY 325. NY 324 was extended northward to NY 384 in Niagara Falls c. 1937, supplanting the entirety of NY 325. The NY 325 designation was reassigned to the short piece of Sheridan Drive not designated as NY 324. The route was extended one final time by 1948 to follow NY 384 westward from the North Grand Island Bridge into downtown Niagara Falls.
