The Assabet River Rail Trail, Inc. (ARRT) is a non-profit organization formed for the purpose of promoting the creation of a multi-use recreational rail trail that will pass through the communities of Marlborough, Hudson, Stow, Maynard and Acton. The trail will be built along the abandoned rail bed of the former Marlborough Branch RR, which was active between 1853 and 1980.

As of August 2018, a 9.2 mile section of the trail is paved and open to the public.

In 1992 two Hudson residents envisioned a rail trail linking the communities of Marlborough, Hudson, Stow, Maynard and Acton. Following the abandoned MBTA rail bed, much of this trail parallels the Assabet River. A volunteer group was organized to promote the Assabet River Rail Trail (ARRT) idea.

Through trail walks, slide shows and talks, the group presented this vision for the 12 mile 'linear park' to selectmen, planning boards, conservation commissions and civic organizations. The members garnered support from the Organization for the Assabet River, the Sudbury Valley Trustees, executive officers for all five communities, chambers of commerce, and recreation departments, and from Senator Robert Durand and Representative Pat Walrath.

The Massachusetts Department of Environmental Management, the Conservation Fund, and the Franklin Research and Development Corporation provided grants for preliminary design work. Students from the Conway School of Landscape Design prepared architectural drawings of areas along the proposed trail and presented them at a public forum in the spring of 1994. Experts in rail-to-trail conversion participated in panel discussions. In February 1997 a state study of the ARRT concluded the project is feasible and gave recommendations. In the spring of 1998, all 5 towns voted to start the first steps of the project.

ARRT volunteers organize trail clean-ups as well as bicycling, hiking and skiing activities along the proposed route. Please join us to enhance the quality of life in our community.