The N11 is a national route in South Africa which runs from the Botswana border at Groblersbrug, through Mokopane, Middelburg, Ermelo and Newcastle to end at the N3 just after Ladysmith.

The R33 joins the N11 and they become one road southwards into the town of Marble Hall (15 kilometres), where they meet the north-eastern terminus of the R573 from Pretoria and KwaMhlanga.

The N11 continues southwards for 85 kilometers, following the Olifants River, to cross into the Mpumalanga Province and reach the city of Middelburg.

At Voortrekker Street south of Ermelo town centre, the N11 meets the terminus of the N2 from Piet Retief, St. Lucia and Durban.

It crosses the Klip River in the city centre and turns westwards to reach an off-ramp intersection with the R103 road adjacent to the Ladysmith Airport entrance.

The N11 heads westwards for 13 kilometres, meeting the north-eastern terminus of the R600 (which connects to Winterton), to reach its end at an off-ramp junction with the N3 highway just south of the N3's Tugela Toll Plaza (each ramp onto the N3 has a tollgate).