Outside of those communities the route is generally forested, but provides access to recreational cottages surrounding the many lakes that dot the region.

Highway 503 was a 116.8 km (72.6 mi) route that travelled through the counties of Victoria (now Kawartha Lakes), Peterborough and Haliburton.

[3][4] Beginning in Kirkfield, the former highway travels north as a continuation of Kawartha Lakes City Road 6, which it is designated as to Sebright.

Surrounded by the grasslands that thrive in the thin soils of the Carden Alvar Provincial Park, it zig-zags northwest to Dalrymple before turning north along the Kawartha Lakes – Simcoe County boundary.

The route follows a straight line the majority of the distance between Dongola and Kinmount, where it encounters a former portion of Highway 121.

It continues to meander alongside the Irondale River into Gooderham, intersecting the northern end of former Highway 507.

[10][11] On March 1,[citation needed] 1964, several highways in the Haliburton and Bancroft area were renumbered in an effort to simplify the road network.

[12] This brought it to its peak length of 116.8 km (72.6 mi) and established the route it would follow until it was decommissioned in the late 1990s.

[14][15] As part of a series of budget cuts initiated by premier Mike Harris under his Common Sense Revolution platform in 1995, numerous highways deemed to no longer be of significance to the provincial network were decommissioned and responsibility for the routes transferred to a lower level of government, a process referred to as downloading.

[4] The following table lists the major junctions along Highway 503, as noted by the Ministry of Transportation of Ontario.