Expressway S61 (Poland)

Expressway S61 or express road S61 is a Polish highway running from Ostrów Mazowiecka (separating from express road S8) to the Polish-Lithuanian border near Budzisko (continuing as the Lithuanian A5 highway). The route was completed in October 2025.

The road is part of the strategically important Via Baltica, the segment from Tallinn to Warsaw of the European route E67 connecting the Baltic States with the rest of Europe through the exposed Suwałki corridor. Its north-eastern end is also part of the planned Via Carpathia. Across the Lithuanian border the preexisting A5 highway to Kaunas is being upgraded into a divided highway with grade-separated junctions, bringing it to the same standard as the S61 expressway.