which political party has a stronghold in the state?
The Republican Party
Michigan
The Republican Party holds a majority in both the House and Senate of the Michigan Legislature. 
where is the interstate located? In the US state of Michigan. how does the route look like? The freeway curves southeasterly and then northeasterly through the complex as it runs eastward through the adjacent residential subdivisions. are there any international crossings around the state where the interstate is? UNANSWERABLE
wiki:25656362
Michigan [SEP] Politics
Michigan voters commonly elect candidates from both major parties, and it is generally regarded as a "swing" state which can be won by either Democratic or Republican presidential candidates. Governors since the 1970s have alternated between the two parties, and statewide offices including attorney general, secretary of state, and senator have been held by members of both parties in varying proportion. The Republican Party holds a majority in both the House and Senate of the Michigan Legislature. The state's congressional delegation is commonly split, with one party or the other typically holding a narrow majority. Republican strongholds of the state include rural areas of Western and Northern Michigan, the Upper Peninsula, the suburbs around Grand Rapids, and Livingston County.