Josefův Důl is a municipality and village in Mladá Boleslav District in the Central Bohemian Region of the Czech Republic. It has about 400 inhabitants.

The name means "Josef's valley". The village was named after its founder Josef Bolza.

Josefův Důl is located about 3 kilometres (2 mi) north of Mladá Boleslav and 47 km (29 mi) northeast of Prague. With an area of 0.66 km (0.25 sq mi), it belongs to the smallest municipalities in the country. It lies in the Jizera Table. The municipality is situated on the left bank of the Jizera River, in a meander, which forms the northern and western municipal border.

The area originally belonged to Kosmonosy, which was bought by Countess Marie Johana Bolza-Martinic in 1760. Josefův Důl was founded as a workers' colony in 1764, when a dyehouse was established here by Count Josef Bolza and its employees settled in its vicinity. The name Josefův Důl first appeared in 1790.

Historical population

Year Pop. ±% 1869 254 —     1880 374 +47.2% 1890 371 −0.8% 1900 372 +0.3% 1910 427 +14.8%	Year Pop. ±% 1921 317 −25.8% 1930 426 +34.4% 1950 406 −4.7% 1961 493 +21.4% 1970 512 +3.9%	Year Pop. ±% 1980 447 −12.7% 1991 381 −14.8% 2001 451 +18.4% 2011 430 −4.7% 2021 388 −9.8%
Source: Censuses

There are no railways or major roads passing through the municipality.

The most valuable building in Josefův Důl is the so-called Josefův Důl Castle. It is a Neo-Renaissance villa built after 1860 for the then owner of the local factory, Friedrich von Leitenberger.

• Official website