The largely wooded corridor was created along the
right-of-way of the old
Little Miami Railroad. The original railway bed is still visible beside the trail in various places along the trail route. Together with the Ohio Department of Natural Resources, the local governments of
Xenia and
Yellow Springs purchased land along the abandoned railroad from 1973 to 1983. In 1979, the land became an Ohio State Park. The trail was strongly supported by residents and officials in Loveland, where a park was being developed around the
Loveland Bike Trail, but was opposed by residents of
Terrace Park, who were concerned about crime. The first of the trail from
Morrow to Loveland was paved in late 1983 and officially opened on May 16, 1984. Two years later, the
Ohio Department of Transportation received a grant from the
Federal Highway Administration to complete the trail. the trail officially stretched from
Spring Valley in
Greene County to the
Terrace Park village limit in
Hamilton County, across the river from
Milford. The trail was extended northward to Xenia later that year and to
Springfield in 1998. In 2006, after a protracted, 26-year battle with Terrace Park residents, it was extended southward to
Newtown. In the late 2000s, state budget cuts caused portions of the trail to fall into disrepair, resulting in the temporary closure of some
wooden bridges and
rest areas. However, an organization called the Friends of the Little Miami State Park Group was founded late 2008 to focus attention and finances on critical portions to keep the trail open and make it safer. Most of the bridges within state park boundaries were paved or re-planked in 2009. In 2010, a failed parks levy prompted the
Clark County Park District to indefinitely close its stretch of the trail, posting "No
Trespassing" signs at park entrances. Because this stretch of trail was partially built with federal funds, the
Ohio Department of Natural Resources attempted to force its reopening. The district reopened its parks in April 2011 with volunteer support. Originally designated State Bike Route 1, the Little Miami Scenic Trail was renumbered in 2011 as State Bike Route 1 south of
Xenia and State Bike Route 3 throughout. The concurrency from Newtown to Xenia is marked with "⅓" signs. However, the
Ohio Department of Transportation later planned to designate State Bike Route 1, including the Little Miami Scenic Trail south of Xenia, as USBR 21;
USBR 25 would instead follow the
Great Miami River Recreation Trail to the west. ODOT formally proposed a USBR 21 alignment to the
American Association of State Highway and Transportation Officials in spring 2021, which the committee approved. In 2022, a dedicated bridge opened in Cincinnati, spanning the
Little Miami River and connecting the trail to other trails toward Downtown Cincinnati. ==Current route==