Addo Heights is a Farm and is located in Cacadu District Municipality, Eastern Cape, South Africa. The estimate terrain elevation Above Sea Level is 263 Metres.

Elavation above Uitenhage. The name is Khoikhoi meaning: 'Passage where succulents grow'. 
This is an official Pass as logged on the Government maps, but when you drive it, you will wonder which cartographer had the courage to name this Road a Pass as there is very little that resembles a real mountain pass, other than it's vertical profile. Despite its very long length of 18,7 km and a respectable altitude variance of 286 m, it only has 10 bends, corners and curves and none of them exceeds 30 degrees radius.
What you will enjoy is a feeling of remoteness in the dense Addo bush and the possibility of spotting game. This Pass will only be driven by the more serious Pass enthusiast. The usual Eastern Cape cautionaries apply of corrugations, and loose gravel on corners as well as livestock and pedestrians on the Road.

Geolocation
25° 18' 36", -33° 12'
References

New Dictionary of South African Names by Peter E Raper

https://mountainpassessouthafrica.co.za/find-a-pass/eastern-cape/item/1370-addo-heights-pass.html

http://za.geoview.info/addo_heights,1023669