According to the 2021 census, it has 77,592 inhabitants; its capital, Tripoli, has about 30,400 residents in the city proper, and about 44,000 total in the greater metropolitan area.

Its climate features hot summers and mild winters in the east, the south, and those parts of the central area that are less than 1000 meters above sea level.

[3] The peculiarity of the plains and basins is a result of intensive karstification: Water seeps into the underground, rather than eroding and draining the topography by surface waterways.

[4][5] The additional problem for rural activities in the basins: When winter rains are heavy, the ground is flooded or temporary lakes arise, even today, as drainage through katavothres is often too slow to start cultivation in due time.

After the Fourth Crusade, the area became a part of the Principality of Achaea, but was progressively recovered by the Byzantine Greeks of the Despotate of the Morea from the 1260s on, a process that was completed in 1320.

After a victorious revolutionary war, Arcadia was finally incorporated into the newly created Greek state.

In 2008, a theory proposed by classicist Christos Mergoupis suggested that the mummified remains of Alexander the Great (not his actual tomb), may in fact be located in Gortynia-Arkadia, in the Peloponnese of Greece.

Tsan is a letter of the Greek alphabet occurring only in Arcadia, shaped like Cyrillic И; it represents an affricate that developed from labiovelars in context where they became t in other dialects.

The Tsakonian language, still spoken on the coast of modern Arcadia (but in the Classical period considered the southern Argolid coast immediately adjoining Arcadia), is a descendant of Doric Greek, and as such is an exceptional example of a surviving regional dialect of archaic Greek.

The main towns in modern Arcadia are Tripoli, Astros, Vytina, Dimitsana, Lagkadia, Tyros, Leonidio, Levidi, Megalopoli and Stemnitsa.

Ancient cities include Acacesium, Asea, Astros, Athinaio, Daseae, Falaisia (Phalesia), Gortys, Hypsus (Stemnitsa), Heraia, Lusi, Lykaio, Lycosura, Mantineia, Megalopolis, Orchomenus (Orchomenos), Tegea, Thoknia, Trapezus, Trikolonoi, Tropaia, Tripoli, Tyros, other cities includes Basilis, Caphyae, Charisia, Ellison, Enispe, Kaous, Karyes, Methydrio, Melangeia, Oryx, Paroria, Pelagos, Rhipe, Stratia, Teuthis and several more.

A thermoelectric power station which produces electricity for most of southern Greece, operates to the south of Megalopolis, along with a coal mine.