Cooma Cottage, Heritage colonial homestead in Yass Valley, Australia.

Cooma Cottage is a former farm and tuberculosis sanatorium on 100 acres at Marchmont, near Yass, built from 1830 to 1837 by Cornelius and Rebecca O'Brien. The original north-facing timber bungalow was expanded by Hamilton Hume from 1839 with about 20 rooms, forming a Palladian composition centred on a portico. The complex includes a stables block attributed to Goulburn architect James Sinclair.

The noted explorer Hamilton Hume purchased the property in 1839 and made it his home until his death in 1873. Hume's acquisition was tied to his exploration of the Yass region, which drove development of the area.

The name Cooma is said to come from the diminutive of County Murray (Co. Mur), the region where the cottage lies; Yass's main street, Comur Street, is pronounced the same. Hamilton Hume headed letters simply "Cooma, Yass". Original furnishings left with John Kennedy Hume's family; some were later gifted to the Yass Historical Society and are on loan to the National Trust.

Cooma Cottage stands on Yass Valley Way at Marchmont, near Yass in the Southern Tablelands. The house museum is run by the National Trust of Australia (NSW), so check opening days and tour times before travelling. The grounds are uneven in places, and the Picconia and other plantings are best seen on foot.

Hume ordered mulberry trees, white figs, two Moorepark apricots and 12 common laurel trees from Camden Park nursery in 1850, and kept vineyards at Cooma Cottage in the 1860s. The Picconia, a relative of the olive, is rare in Australia and almost extinct in its native Canary Islands.