Zilwaukee Bridge.
Interstate 675 (I-675) is a 7.7-mile-long (12.4 km) auxiliary Interstate Highway, state trunkline highway and loop route in the US state of Michigan. Splitting from I-75 and US Highway 23, which run north concurrently along the eastern side of Saginaw, I-675 heads west into the downtown area and spans the Saginaw River on the Henry G. Marsh Bridge. After an interchange with M-58, the Interstate turns northward, then runs northeasterly to connect back to I-75. The Marsh Bridge was constructed as an alternative to the Zilwaukee Bridge, which is just southeast of this junction on I-75 over the Saginaw; the I-75 bridge was until 1988 a drawbridge that would impede traffic on the freeway for up to four hours at a time. Construction of I-675 started in 1969 and the freeway opened in 1971. Sections near downtown were reconstructed from 2009 through 2011 to update one of the freeway's interchanges and to rebuild the Marsh Bridge.
