When does Bonanza return?

Bonanza is an American Western television series that ran on NBC from September 12, 1959, to January 16, 1973. The show is set in the 1860s and centers on the Cartwright family, who live in the vicinity of Virginia City, Nevada, bordering Lake Tahoe. The title "Bonanza" is a term used by miners in regard to a large vein or deposit of silver ore, from Spanish bonanza (rich ore body) In 2002, Bonanza was ranked No. 43 on TV Guide's 50 Greatest TV Shows of All Time.
The show chronicles the weekly adventures of the Cartwright family, headed by the thrice-widowed patriarch Ben Cartwright. The family lived on a thousand-square-mile (2,600 km2) ranch called the Ponderosa on the eastern shore of Lake Tahoe in Nevada opposite California on the edge of the Sierra Nevada range. The ranch name refers to the Pinus ponderosa (ponderosa pine)