Bridge, proceeds west through Flint, then Lansing, and then turns south to Angola, Indiana. has its eastern terminus at the U.S. side of the Blue Water Bridge in Port Huron, Michigan, at the Sarnia, Ontario, Canada border, where together with I-69 it meets Ontario Highway 402. is a highway of an arc-like shape closely following the outline of the Thumb along the Lake Huron/Saginaw Bay shoreline between Port Huron and Bay City. It is generally a scenic drive. is a cross peninsular road, running across the mitten and the Thumb—from Port Sanilac on the Lake Huron shore; through Saginaw near Saginaw Bay; and then on to Muskegon on the Lake Michigan shore. This east-west surface route nearly bisects the Lower Peninsula of Michigan latitudinally. is a gateway route to The Thumb of Michigan, carrying vacationers to the resorts and cottages on Saginaw Bay and Lake Huron in the vicinity of Caseville and Port Austin. It goes up the middle of the Thumb, and directly connects in Macomb County, Michigan to the M-53 expressway. It is an important route for agricultural and manufactured goods. Rail Area Amtrak stations are in Lapeer, Port Huron, and Flint. Local railroads are the Grand Trunk Western Railroad, CSX Transportation, Canadian National Railway, and the Huron and Eastern Railway. Pere Marquette Railway was a railroad that had lines throughout the Thumb; its lines are now either abandoned or in use by CSX, or Huron and Eastern. Major railroad centers are Vassar, Bad Axe and Port Huron. Airports The only international airport in the Thumb is St. Clair County International Airport about outside Port Huron. City airports include: Caro Municipal, Dupont-Lapeer Airport, Huron County Memorial Airport, Marine City Airport, Marlette Municipal, Sandusky City, and Yale Airport. Scheduled airline service is available from MBS International Airport in Freeland, Michigan and Flint Bishop International Airport. While neither of these airports is in the Thumb, both are relatively close by. Area codes Area code 989 covers about half of the Thumb: Huron, Tuscola, and far northern Sanilac County (and the Marlette, Michigan area). The Thumb's other half is covered by area code 810, which takes in most of Sanilac, Lapeer, Genesee and Saint Clair Counties. All of Macomb County is served by area code 586, as is a small part of south-western Saint Clair County. See also State Michigan Regional Flint/Tri-Cities and Tri-Cities Lake Huron Metro Detroit Counties List of