| Jerwen County | |
| Native Name: | Вейсенштейнскій уѣздъ |
| Native Name Lang: | ru |
| Settlement Type: | Uezd |
| Mapsize: | 225px |
| Subdivision Type: | Country |
| Subdivision Name: | Russian Empire |
| Subdivision Type1: | Governorate |
| Subdivision Name1: | Estonia |
| Established Title: | Established |
| Established Date: | 1745 |
| Extinct Title: | Abolished |
| Extinct Date: | 1920 |
| Seat Type: | Capital |
| Seat: | Veysenshteyn |
| Area Total Km2: | 2871.21 |
| Population As Of: | 1897 |
| Population Total: | 52,673 |
| Population Density Km2: | auto |
Jerwen County (German: Kreis Jerwen or German: Kreis Weissenstein, Estonian: Järva kreis or Estonian: Paide kreis, Russian: Вейсенштейнскій/Еервенскій уѣздъ|Veysenshteynskiy/Yervenskiy uyezd) was one of the four counties of the Russian Empire located in the Governorate of Estonia.[1] It was situated in the central part of the governorate (in present-day northern Estonia). Its capital was Paide (Weissenstein). The territory of Jerwen County corresponds to most of present-day Järva County and small parts of Lääne-Viru and Rapla counties.[2]
At the time of the Russian Empire Census of 1897, Jerwen County had a population of 52,673. Of these, 96.7% spoke Estonian, 2.2% German, 0.8% Russian, 0.1% Yiddish and 0.1% Latvian as their native language.[3]