Explore the Family Name Koslowski

The meaning of Koslowski

1. Germanized or Americanized form Polish Kozłowski (see Kozlowski). 2. Jewish (eastern Ashkenazic): variant of Kozlowski (from Poland) or Kozlovsky. Compare Kosloski and Koslowsky. Some characteristic forenames: German Gerda, Hans, Klaus, Kurt, Otto.

Dictionary of American Family Names, 2nd edition, © Oxford University Press, 2022.

How common is the last name Koslowski in the United States?

According to the Decennial U.S. Census, the surname Koslowski saw a drop in popularity between 2000 and 2010. In 2000, it ranked as the 28,994th most common surname, whereas by 2010, it had slipped to 32,599th. The total count of individuals with this last name also decreased over this period, from 771 in 2000 to 705 in 2010—a decline of 8.56%. Consequently, the proportion of people named Koslowski per 100,000 residents dropped by 17.24%.

	2000	2010	Change
Rank	#28,994	#32,599	-12.43%
Count	771	705	-8.56%
Proportion per 100k	0.29	0.24	-17.24%

Race and Ethnicity of people with the last name Koslowski

In terms of ethnicity, the same data from the Decennial U.S. Census shows a small shift in the distribution between 2000 and 2010. Notably, the percentage of Koslowskis identifying as Hispanic nearly doubled, rising from 1.30% to 2.41%. At the same time, the proportion identifying as White decreased slightly from 95.85% to 94.61%. The percentage of individuals with this surname who identified as Asian/Pacific Islander changed from zero in 2000 to 1.28% in 2010. No change was observed for those identifying as Black. Additionally, the percentage of American Indian and Alaskan Native individuals named Koslowski dropped from 1.04% in 2000 to none in 2010. Meanwhile, the percentage of those reporting two or more ethnic identities increased from 1.43% to 1.56%.

	2000	2010	Change
White	95.85%	94.61%	-1.29%
Hispanic	1.3%	2.41%	85.38%
Two or More Races	1.43%	1.56%	9.09%
Asian/Pacific Islander	0%	1.28%	0%
Black	0%	0%	0%
American Indian and Alaskan Native	1.04%	0%	0%