State Route 229 begins at an intersection with U.S. Route 1A (Main Street) in downtown Limestone. The route progresses eastward as a side street known as Bridge Street for one block to the intersection with Church Street, where the name switches over to Grand Falls Road. At this intersection, the road turns from east to the northeast. Route 229 crosses over a railroad track and leaves downtown Limestone, passing to the south of Limestone Pond. The route passes several residences and periods of large farms and grasslands surrounding the two-lane highway. Just before the intersection with Morris Road, Route 229 makes a short turn further northeast and intersects with Blake Road and Nike Road. Just after the intersection with Nike Road, Route 229 passes one farm and the 24-hour US Customs station at the Maine/New Brunswick state/provincial line. At the Canadian border, Route 229 ends and continues eastward in New Brunswick as Route 375.