The area around the modern town has been inhabited since the Neolithic. Part of Justinian I's defensive system in the 6th century, the region gained importance as part of the First Bulgarian Empire due to the proximity to the capitals Pliska and Preslav and the passes of Stara Planina.
The first written evidence of the modern town dates from the 17th century, when it was mentioned as the kaza centre Osman Pazarı in Ottoman tax registers. The settlement was a centre of craftsmanship and trade.
Omurtag acquired its present name in 1934, named after the Bulgarian khanOmurtag.
On 24 February 2020 during strong winds knocked down the minaret of the 1874 mosque. The building itself survived with only minor damage to the roof, but the minaret was completely destroyed. As of 2021 the mosque is still under reconstruction.
Population
Omurtag
Year
1887
1910
1934
1946
1956
1965
1975
1985
1992
2001
2005
2009
2011
2021
Population
no data
no data
no data
4,233
6,127
8,161
9,082
9,505
8,941
8,893
8,867
8,725
7,369
??
Highest number 10,160 in 1980
Sources: National Statistical Institute,[1][2][3] citypopulation.de,[4] pop-stat.mashke.org,[5] Bulgarian Academy of Sciences[6]