In the U.S. state of Rhode Island, U.S. Route 1 is a major north–south state highway through Providence. Staying close to the Atlantic Ocean and Narragansett Bay, it is a longer route than Interstate 95, and many portions are a four-lane divided highway.

US 1 has a business/bypass split in Warwick where US 1 Business runs along Post Road and US 1 Bypass runs along Post Road Bypass. The business route is officially recognized by the Rhode Island Department of Transportation as US 1.

US 1 enters Rhode Island via a small bridge from Pawcatuck, CT to Downtown Westerly. Route 1 winds through Downtown Westerly, passing two shopping plazas (the Granite Street Shopping Center and the Franklin Shopping Plaza) prior to a junction with RI 78, the two-lane highway designed to bypass Downtown. A right onto Airport Road at this intersection provides access to Westerly State Airport, Watch Hill and Misquamicut. Route 1 continues to Dunn's Corners, with Langworthy Road providing more beach access. The road then becomes a divided highway shortly after, with RI 1A merging into the highway from the Misquamicut area. Route 1 then crosses into Charlestown, RI near Shelter Harbor. After stoplight intersections with Ross Hill Road (RI 216), West Beach Road-providing access to Quonochontaug, East Beach Road-providing access to Blue Shutters Town Beach and East Beach, and Wildflower Road, there are no more stoplights until the end of the freeway after the Wakefield, RI exits. Access to exits on the opposite side of the road are provided through u-turn ramps. The southbound side has junction with Prosser Trail, a road leading to Burlingame State Park. Burlingame access is also located prior to the East Beach Road exit. An exit for Route 1A on the northbound side leads to Ningret Park and the police station. Route 1 bends to the right. On the southbound side is Kings Factory Road. Another junction with Route 1A occurs on Route 1 North. 1A merges onto 1 from the south, briefly, before exiting and continuing north to Cross Mills. Route 1 north then features a ramp providing access to Cross Mills and Route 1A-leading to Charlestown Breachway and Charlestown Town Beach-for those just merging in on a u-turn from Route 1 south via a junction with RI 2 / RI 112 (South County Trail). Another set of u-turn ramps is located for access to Routes 2 and 112. After northbound junctions with more beach access roads (Falcone Lane, Narrow Lane, which is split in half by the highway, the other half continuing on the southbound side that leads to South County Trail), US 1 continues into South Kingstown, where Green Hill Beach Road (Route 1A) meets US 1 on the northbound side, and Post Road (also Route 1A) meets Route 1 south. After a junction with Moonstone Beach Road (northbound side leads to the Trustom Pond National Wildlife Refuge, southbound side leads to Perryville), RI 110 meets Route 1 south. Prior to this on the southbound side, Route 1A meets Route 1. Back to the northbound side, where Matunuck Beach Road is found, leading to the beachdise community of Matunuck, RI. Following this is Succotash Road, which leads to Jerusalem, RI, Snug Harbor, and East Matunuck State Beach. Then comes Post Road, leading to the signed destination-Jerry Brown Farm Road. Another Post Road/Route 1A junction comes on US 1 north, before it meets the highway again after a brief exitless stint. Route 1 south's junction with Post Road/Route 1A north leads to Wakefield and Peace-Dale. The road becomes a freeway and has two exits for the Salt Pond/South County Hospital area. A third exit leads to RI 108 and Narragansett's town beach, Galilee, and Point Judith. A Wakefield exit marks the end of the freeway. Access to South County Commons comes soon. RI 138 meets from the west, and stays on in the concurrency until the exits for access to the Jamestown Verrazzano Bridge and Jamestown, and the Claiborne Pell Newport Bridge and Newport. Route 1 then meets RI 4, a thruway leading to I-95.

US 1 takes the following route through the state (south to north):

Except north of downtown Providence, where US 1 was built as the Providence and Pawtucket Turnpike (now Main Street), the highway was never a turnpike road. Portions are the old Boston Post Road, while other parts were built as bypasses, leaving the old road as Route 1A. The turnpike south of Providence â€” the Providence and Pawcatuck Turnpike and Hopkinton and Richmond Turnpike - followed the diagonal route that I-95 now takes.