The highway 70 state line crossing between Minnesota and Wisconsin is somewhat unusual in that these two state highways keep the same number on both sides of the state line. While that is standard for Interstate and US highways, it is uncommon for state highways. In Wisconsin, WI-70 started as a 10 mile long route in 1917 running from Grantsburg east to WI-35. In 1929, the Grantsburg Toll Bridge over the St. Croix River was completed, and WI-70 was extended to the state line. On the Minnesota side, MN-70 was authorized in 1933, and numbered to match WI-70. It was paved in 1949. Today, both MN-70 and WI-70 combine to serve as an alternate route to the northern Wisconsin recreation areas for traffic to avoid congested highway US-8.

The old Grantsburg Toll Bridge was removed and replaced in 1991 by this modern steel girder bridge. The new bridge was built purely for function, and is devoid of any decorative features. It does have, however, the current favored guardrails. These are the type where the concrete has an angle to help absorb some crash forces, and the concrete is solid at the bridge deck level so no road debris can wash into the river.

This bridge has a DNR vistor center on the Minnesota side, and a rest area on the Wisconsin side. The site is complete with trails that take you to the river, under the bridge, and connect with the regional trail system.