The Orange Free State (Dutch: Oranje-Vrijstaat,Afrikaans: Oranje-Vrystaat, abbreviated as OVS) was an independent Boer sovereign republic in southern Africa during the second half of the 19th century, and later a British colony and a province of the Union of South Africa. It is the historical precursor to the present-day Free State province. Extending between the Orange and Vaal rivers, its borders were determined by the United Kingdom of Great Britain and Ireland in 1848 when the region was proclaimed as the Orange River Sovereignty, with a seat of a British Resident in Bloemfontein.

In the northern part of the territory a Voortrekker Republic was established at Winburg in 1837. This state merged with the Republic of Potchefstroom which later formed part of the South African Republic (Transvaal).

Following the granting of sovereignty to the Transvaal Republic, the British recognised the independence of the Orange River Sovereignty on 17 February 1854 and the country officially became independent as the Orange Free State on 23 February 1854, with the signing of the Orange River Convention. The new republic incorporated both the Orange River Sovereignty and the traditions of the Winburg-Potchefstroom Republic.

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