US Highway 16 (US 16), also called Grand River Avenue for much of its length in the state, was one of the principal pre-Interstate roads in the state of Michigan. Before the creation of the United States Numbered Highway System in 1926, the highway had been designated M-16. The modern route of Grand River Avenue cuts across the Lower Peninsula in a northwest–southeast fashion from near Grand Rapids to Detroit. Before the late 1950s and early 1960s, US 16 followed other roads between Muskegon and Grand Rapids, and then Grand River Avenue through Lansing to Detroit. With the coming of the Interstate Highway System, US 16 was shifted from the older roads to the newer freeways. When the gap in the freeway was filled in around Lansing, the US 16 designation was decommissioned in the state. The freeway was then designated Interstate 96 (I-96) east of Grand Rapids or I-196 west of that city.