The R371 in Co. Roscommon – looking north-northeast into Co. Leitrim in the distance
The R371 connects two crossings of the Shannon which lie 18 km apart as the crow flies – though considerably further as the salmon swims ...and as the road runs – there being only one intermediate bridge over Britain and Ireland's longest river.
It begins at a roundabout on the N4 at Tomisky, which is in County Longford, but the road remains in that county for only 300 m before entering Leitrim. We are at first running north-by-northwest along the left (eastern) bank of the Shannon; this is good quality S2, having been part of the N4 until 2007. After 1400 m, the old N4 becomes the L1601 and the R371 turns left to cross Roosky Bridge, and yet another boundary, so that we now find ourselves in County Roscommon.
From Roosky the remaining 24 km are all in Roscommon, the route heading first west, then southwest, to an intersection with the N5 at Scramoge, before finally turning south-by-southeastward to reach Ballyleague on the N63, 300 m short of the Lanesborough Bridge crossing of the Shannon. The final 11 km of the R371 is a stretch of almost Roman (though actually early-19th-century surveyors') near-perfect straightness.