It covers the lower inland slopes of the Great Dividing Range, extending from north of Dunedoo through central NSW and into north-east Victoria, meeting its south-western end around Beechworth.

[3] The bioregion is divided into three sub-regions: [4] Mean annual temperatures in the region range from very cool to warm; from just 8 °C (46 °F) up to 17 °C (63 °F) depending on altitude and latitude.

This is due to being windward of the Great Dividing Range, with the prevailing westerly airmasses and accompanying cloud cover bringing low maximum temperatures in winter; and the far inland location, prolonging heatwaves in summer.

These areas have a climate that is more similar to that of Adelaide and Perth, than the proximate cities like Sydney and Wollongong, with their wet winters and relatively dry summers.

[9][10] The South Western Slopes were occupied by the Wiradjuri people, the largest Aboriginal language group in NSW.

[11] Notable towns and cities within the bioregion, from Beechworth in the south-west to Dunedoo in the north-east, include Wodonga, Albury, Corryong, Tumbarumba, Batlow, Narrandera, Wagga Wagga, Junee, Tumut, Gundagai, Cootamundra, Temora, West Wyalong, Grenfell, Young, Cowra, Forbes, Parkes, Wellington and Mudgee.