HOUSTON, Sept. 22 - When Angola recently opened its only consulate outside New York, few people here were surprised that Houston was chosen.

Texas already leads the nation in trade and commerce with Africa. More than 1,000 Houston companies do business there, and 60 have significant subsidiaries on the continent, according to the city of Houston.

The city may have a way to go before it becomes a de facto commercial capital to Africa the way Miami is for much of Latin America, but it is becoming increasingly important to African commerce and diplomacy. And the city is becoming a significant starting point for affluent Africans seeking to do business in the United States.

The reason is oil. This is the energy capital of the United States, and West African countries like Angola, Equatorial Guinea and Nigeria are increasingly important suppliers of oil. They already account for about 14 percent of all American oil imports, and are forecast to supply 20 percent soon.