Udvarhely () was an administrative county (comitatus) of the Kingdom of Hungary. Its territory is now in central Romania (eastern Transylvania). The capital of the county was Székelyudvarhely (now Odorheiu Secuiesc).
Geography
thumb|left|alt=Map of Udvarhely county in the Kingdom of Hungary|Map of Udvarhely, 1891.
Udvarhely county shared borders with the counties of Maros-Torda, Csík, Háromszék, Nagy-Küküllő, and Kis-Küküllő. The county lay in the Carpathian Mountains. Its area was 2,938 km<sup>2</sup> around 1910.
History
Udvarhely county consisted of three former seats of the Székelys: Udvarhelyszék, Bardóc and Keresztúr (the latter two as filial seats of the former). It was formed in 1876, when the administrative structure of Transylvania was changed. In 1920, by the Treaty of Trianon, the county became part of Romania until 1940 when, by the Second Vienna Award, much of its territory was reassigned to Hungary. After the end of World War II it became again part of Romania. Most of its territory lies in the present-day Romanian county of Harghita, with small parts in Mureș (a small part in the west) and Covasna (a small part in the south-east).
Demographics
thumb|right|200 px|Ethnic map of the county with data of the 1910 census (see the key in the description)
{| class="wikitable"
|+ Population by mother tongue
! Census !! Total !! Hungarian !! Romanian !! German !! Other or unknown
|-
! 1880
| 105,520 || 94,311 (92.79%) || 3,099 (3.05%) || 2,322 (2.28%) || 1,910 (1.88%)
|-
! 1890
| 110,132 || 103,209 (93.71%) || 3,191 (2.90%) || 2,131 (1.93%) || 1,601 (1,45%)
|-
! 1900
| 118,275 || 112,607 (95.21%) || 2,928 (2.48%) || 2,225 (1.88%) || 515 (0.44%)
|-
! 1910
| 124,173 || 118,458 (95.40%) || 2,840 (2.29%) || 2,202 (1.77%) || 673 (0.54%)
|-
|}
{| class="wikitable"
|+ Population by religion
! Census !! Total !! Roman Catholic !! Calvinist !! Unitarian !! Eastern Orthodox !! Lutheran !! Greek Catholic !! Jewish !! Other or unknown
|-
! 1880
| 105,520 || 35,050 (33.22%) || 36,533 (34.62%) || 24,451 (23.17%) || 4,121 (3.91%) || 2,747 (2.60%) || 2,010 (1.90%) || 581 (0.55%) || 27 (0.03%)
|-
! 1890
| 110,132 || 37,287 (33.86%) || 37,826 (34.35%) || 25,544 (23.19%) || 4,171 (3.79%) || 2,777 (2.52%) || 1,745 (1.58%) || 768 (0.70%) || 14 (0.01%)
|-
! 1900
| 118,275 || 41,893 (35.42%) || 40,237 (34.02%) || 26,614 (22.50%) || 4,101 (3.47%) || 2,830 (2.39%) || 1,387 (1.17%) || 1,204 (1.02%) || 9 (0.01%)
|-
! 1910
| 124,173 || 45,116 (36.33%) || 41,632 (33.53%) || 27,567 (22.20%) || 4,020 (3.24%) || 2,991 (2.41%) || 1,508 (1.21%) || 1,313 (1.06%) || 26 (0.02%)
|-
|}
Subdivisions
thumb|right|300px| Contemporary map of the county
In the early 20th century, the subdivisions of Udvarhely county were:
{| class="wikitable"
!colspan=2|Districts (járás)
|-
! District!! Capital
|-
| Homoród||Oklánd (now Ocland)
|-
|Parajd '||Parajd (now Praid)
|-
| Székelykeresztúr||Székelykeresztúr (now Cristuru Secuiesc)
|-
| Udvarhely||Székelyudvarhely (now Odorheiu Secuiesc)
|-
!colspan=2|Urban districts (rendezett tanácsú város)
|-
|colspan=2| Székelyudvarhely (now Odorheiu Secuiesc)
|-
|}