Patel is not a single caste. The Patidar community of Gujarat grew out of the Kanbi (Kunbi) cultivator caste — 'Patidar' means holder of a land-strip and 'Patel' comes from Patil, a village-headman title. It has two main divisions — Leuva Patidar (central/south Gujarat, Charotar & Saurashtra; kuldevi Annapurna Devi) and Kadva Patidar (North Gujarat & Kutch; kuldevi Umiya Mata at Unjha) — which traditionally do not intermarry. Other distinct groups using the Patel/Patidar name include Anjana (Chaudhary) Patidar, Matiya Patidar, the Kutch Kadva Patidars and the separate Koli Patel community. For marriage, Patidars rely on the Gam (village-federation) system more than the Brahmanical gotra.
Two main Patidar divisions — Leuva and Kadva — which traditionally do not intermarry, plus distinct groups such as Anjana (Chaudhary) Patidar, Matiya Patidar, Kutch Kadva Patidars and the separate Koli Patel community.
Leuva Patidars are concentrated in central/south Gujarat (Charotar, Saurashtra), revere Annapurna Devi, and by tradition claim descent from Lava; Kadva Patidars are concentrated in North Gujarat, revere Umiya Mata (Unjha), and by tradition claim descent from Kush. The two divisions traditionally do not intermarry.
Patidar/Patel is a Gujarati agrarian landowning community that grew out of the Kanbi cultivator caste. 'Patel' identifies a community family rather than a single sub-caste — your division (Leuva/Kadva) and Gam pin down the specific lineage.
For Patidars the Gam (village grouping, also called Gol) is the primary marriage identifier. Many families also record a Vedic gotra such as Kashyap, Bharadwaj or Vashishtha, but the division (Leuva/Kadva) and the Gam are checked first.