Byafossen is a village in the municipality of Steinkjer in Trøndelag county, Norway. It is located along the river Byaelva, about 3 kilometres (1.9 mi) northeast of the town of Steinkjer and about 6 kilometres (3.7 mi) southwest of the village of Sunnan. The Nordlandsbanen railway line passes through the village, but there is not a station here. The village is named after the local 12.5-metre (41 ft) waterfall on the river. The village is usually considered part of the town of Steinkjer urban area.