As the North Fork extends outside the city limits, Yellow House Canyon gradually widens and deepens.

Where the North Fork crosses Farm to Market Road 400, a large portion of Lubbock's treated sewage is pumped into the stream via a pipeline that empties at a point called Outfall 001.

[6] At the point where the North Fork crosses Lubbock County Road 3600, the canyon is nearly 2 mi (3,000 m) wide and 200 ft (60 m) deep.

To the east of Slaton, the North Fork enters Crosby County, passing to the southwest of Courthouse Mountain and the ghost town of Canyon Valley.

The stream then begins trending in a more easterly direction as it meanders wildly, eventually crossing from Garza into Kent County, where it merges with the Double Mountain Fork.