Individual parcels don’t take elevation into account, but yes, large-scale land surveys do.
The Canadian federal government surveyed the prairies in western Canada in the 19th century, using a large scale grid system. Every so often, the survey lines running north-south are corrected to take curvature into account. North-south grid roads accordingly have a jog every so often, called a correction line. And although Saskatchewan looks like a rectangle, if you zoom in on the Saskatchewan-Manitoba boundary, you’ll see that it has regular little jogs to correct the boundary line as it goes north.