It stretches from Tulbagh in the north to McGregor in the south and Rawsonville in the west to Ashton and Bonnievale in the east.
The main north-south rail and road routes traverse the valley, including the N1 highway linking Cape Town and Johannesburg.
Summers can be very hot, due to its inland location, usually averaging 30 °C from December to March, but sometimes peaking near 40 °C during the hottest of days.
This is due to the Du Toitskloof and Riviersonderend Mountains blocking cooling oceanic breezes from reaching the valley.
Spring and Autumn are transitional periods of variable rainfall, occasional light snow on the highest peaks and mild temperatures.