Karo Regency is a landlocked regency of North Sumatra Province of Indonesia, situated in the Barisan Mountains. The regency, which was established on 7 November 1956, covers an area of 2,127.25 square kilometres (821.34 sq mi) and according to the 2010 census it had a population of 350,479, increasing to 404,998 at the 2020 Census; the official estimate as at mid-2023 was 420,799, comprising 208,600 males and 212,200 females. 60.99% of the regency is forested. Its regency seat is the town of Kabanjahe. The Batak Karo language is spoken in the regency, as well as the Indonesian language. It borders Southeast Aceh Regency in Aceh to the west, Deli Serdang Regency and Langkat Regency to the north, Dairi Regency and Toba Samosir Regency to the south, and Deli Serdang Regency and Simalungun Regency to the east.

The GDP per capita of Karo Regency in 2005 was 11.65 million rupiah, approximately US$1,200. 74% of the population works in agriculture, which comprises 60% of the regional GDP. The second-largest sector is government, which comprises 11% of the regional GDP.

The regency is divided administratively into seventeen districts (kecamatan), tabulated below with their areas and their populations at the 2010 Census and the 2020 Census, together with the official estimates as of mid-2023. The table also includes the locations of the district administrative centres, the number of administrative villages in each district (totaling 259 rural desa and 10 urban kelurahan), and its post codes.

Kode Wilayah	Name of District (kecamatan)	Area in km	Pop'n Census 2010	Pop'n Census 2020	Pop'n Estimate mid 2023	Admin centre	No. of villages	Post code
12.06.10	Mardingding	267.11	17,062	19,954	20,812	Mardingding	12	22165
12.06.09	Laubaleng	252.60	17,713	20,652	21,519	Laubaleng	15	22164
12.06.08	Tigabinanga	160.38	19,900	22,395	23,096	Tigabinanga	20	22162
12.06.07	Juhar	218.56	13,244	14,787	15,215	Juhar Perangin-angin	25	22163
12.06.06	Munte	125.64	19,686	22,909	23,857	Munte	22	22161
12.06.13	Kuta Buluh	195.70	10,586	12,602	13,210	Kutabuluh	16	22155
12.06.11	Payung	47.24	10,837	12,249	12,649	Payung	8	22154
12.06.17	Tiganderket	86.76	13,178	14,555	14,929	Tiganderket	17	22156
12.06.12	Simpang Empat	93.48	19,015	21,355	23,010	Ndokum Siroga	17	22150
12.06.16	Naman Teran	87.82	12,796	14,622	15,147	Naman	14	22151
12.06.15	Merdeka *	44.17	13,310	15,580	16,252	Merdeka	9	22153
12.06.01	Kabanjahe	44.65	63,326	73,581	76,592	Kabanjahe	13	22111 - 22115
12.06.02	Berastagi *	30.50	42,541	48,244	49,866	Berastagi	10	22152
12.06.04	Tigapanah	186.84	29,319	34,263	35,725	Tigapanah	26	22170
12.06.14	Dolat Rakyat *	32.25	8,296	9,848	10,315	Dolat Rakyat	7	22171
12.06.05	Merek	125.51	18,054	22,746	24,240	Garingging	19	22173
12.06.03	Barusjahe *	128.04	22,097	24,656	25,365	Barusjahe	19	22172
	Totals	2,127.25	350,960	404,998	420,799	Kabanjahe	269

Notes: (a) including one kelurahan (Tigabinanga town).
(b) comprising 5 kelurahan (Gung Leto, Gung Negeri, Kampung Dalam, Lau Cimba and Padang Mas) and 8 desa.
(c) comprising 4 kelurahan (Gundaling I, Gundaling Ii, Tambak Lau Mulgap I and Tambak Lau Mulgap Ii) and 6 desa.

Note that four of these districts (indicated by "*" above) constitute a part of the Medan metropolitan area.

3°06′N 98°30′E / 3.100°N 98.500°E / 3.100; 98.500