Geomorphologically, the Little Carpathians belong to the
Alps-Himalaya System, the
Carpathian Mountains sub-system, the
Western Carpathians province, and the
Inner Western Carpathians sub-province. The Little Carpathians are further divided into four parts, from south to north: the
Devín Carpathians (), the
Pezinok Carpathians (), the
Brezová Carpathians () and the
Čachtice Carpathians (). The mountains are densely forested (90% being
broad-leaved trees), and the southeastern part contains extensive vineyards (e.g.
Rača,
Pezinok, and
Modra). Several castles or castle ruins are situated in the Little Carpathians, for example
Devín,
Čachtice,
Červený Kameň, and
Smolenice castles. Geologically, the mountain range is part of the
Tatra-Fatra Belt of core mountains. There are several
active faults which have produced earthquakes. Of them the most notable is the Dobra Voda fault (1906 and 1930 produced 8.5° and 7.5°
EMS-98 or equal to
M_\mathrm{L} = 5.7 and 5.0). This particular fault is closely monitored because of its proximity to the
Bohunice Nuclear Power Plant, approximately 15 km away. The Little Carpathians are seismically one of the most active regions in Slovakia and the epicentres of many earthquakes with an approximate magnitude of 2.5 on the
Richter magnitude scale are located here. There are a total of eight
karst areas in the Little Carpathians: the Devín Carpathians, Borinka (Pajštún), Cajlan, Kuchyňa-orešany, Plavecký, Smolenice, Dobrovodský, and Čachtice karsts. The most important karst forms include the caves Deravá, Tmavá skala, Driny, and Čachtická, and additional caves along the Borinský potok.
Driny, a limestone cave, is the only cave open to the public. Major streams include
Vydrica and
Suchý jarok. == Highest peaks ==