The backbone of the economy has been petroleum, and drilling was mainly undertaken in the Sunzha River valley between Grozny and Gudermes. Petroleum refining was concentrated in Grozny, and pipelines ran to the Caspian Sea (east) at Makhachkala and to the Black Sea (west) at Tuapse. Natural gas is also found in the area. Agriculture is largely concentrated in the Terek and Sunzha valleys. Transportation is mainly by rail, following the Terek and Sunzha valleys and linking with Astrakhan and Baku on the Caspian Sea and with Tuapse and Rostov on the Black Sea and the Sea of Azov. Motor roads join Grozny to other centres within and outside the republic.
