Explore the Family Name Dennehy

The meaning of Dennehy

Irish (Cork and Kerry): either an Anglicized form of Gaelic Ó Duineachdha ‘descendant of Duineachaidh’, a personal name meaning ‘humane’. Some characteristic forenames: Irish Brendan, Donal, Paddy.

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

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

Based on the Decennial U.S. Census data, the surname Dennehy has seen a slight decrease in popularity from 2000 to 2010. In 2000, Dennehy ranked 15,780 in terms of frequency and rose to 16,544 by 2010, indicating a decrease in rank by about 4.84%. Despite this drop in rank, the actual count of people with the surname Dennehy increased from 1,696 to 1,735 — an uptick of 2.3%. However, when considering the proportion per 100,000 individuals, there was a slight decrease of 6.35%, moving from 0.63 to 0.59.

	2000	2010	Change
Rank	#15,780	#16,544	-4.84%
Count	1,696	1,735	2.3%
Proportion per 100k	0.63	0.59	-6.35%

Race and Ethnicity of people with the last name Dennehy

In terms of ethnic identity, the Decennial U.S. Census data reveals some shifts between 2000 and 2010. The majority of people with the Dennehy surname identify as White, although this percentage decreased slightly from 96.46% in 2000 to 95.27% in 2010. Individuals identifying as Asian/Pacific Islander saw a significant increase, rising from 0.29% to 0.63%. There was also a modest increase in those identifying as Hispanic, going from 1.83% to 2.77%. Those identifying with two or more races marginally decreased from 0.88% to 0.81%. There were no recorded individuals with the surname Dennehy who identified as Black or American Indian and Alaskan Native in either year.

	2000	2010	Change
White	96.46%	95.27%	-1.23%
Hispanic	1.83%	2.77%	51.37%
Two or More Races	0.88%	0.81%	-7.95%
Asian/Pacific Islander	0.29%	0.63%	117.24%
Black	0%	0%	0%
American Indian and Alaskan Native	0%	0%	0%