Long time since I came across that story. I suppose the offer must've been made by the colonial gov't.

The offer was first made by British Colonial Secretary Joseph Chamberlain to Theodore Herzl's Zionist group in 1903. He offered 5,000 square miles (13,000 km2) of the Mau Plateau in what is today Kenya. The area was thought suitable because of its temperate hill station-like climate and its relative isolation, being surrounded by the Mau Forest. The offer was a response to pogroms against the Jews in Russia, and it was hoped the area could be a refuge from persecution for the Jewish people.

The idea was brought to the Zionist Congress at its sixth meeting in 1903 in Basel. There a fierce debate ensued. The African land was described as an "ante-chamber to the Holy Land" and a Nachtasyl (temporary night shelter), but other groups felt that accepting the offer would make it more difficult to establish a Jewish state in Ottoman Palestine, and also that the Jewish nation would not be able to claim itself as native to that land, since there were no historic or culture links between the Hebrews and East Africa. Before the vote on the matter, the Russian delegation stormed out in opposition. By a remaining vote of 295 to 177, it was decided to send an "investigatory commission" on expedition to examine the territory proposed.

The next year a three-man delegation was sent to inspect the plateau. Its high elevation gave it a temperate climate, making it suitable for European settlement. However, the observers found a dangerous land filled with lions and other creatures. Moreover, although it was sparsely populated by small bands of Maasai (themselves having recently conquered the Sirikwa tribe), the Maasai were hostile to other tribes and outsiders.

After receiving this report, the following Congress in 1905 decided to politely decline the British offer. Some Jews viewed this as a mistake; they then split from the ZO and established the Jewish Territorialist organization, with the explicit aim of establishing a Jewish state anywhere, not just in Palestine. A few Jews did move to Kenya, but most settled in the urban centres. Some of these families remain to this day.