Explore the Family Name Grennan

The meaning of Grennan

1. English (Lancashire, of Norman origin): nickname for a man with a moustache, from Old French gernon, grenon ‘moustache’. 2. Irish (Offaly, Westmeath and Down): shortened Anglicized form of Gaelic Ó Grianáin (see Greenan). Some characteristic forenames: Irish Brendan, Eamon, Kieran.

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

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

Based on the Decennial U.S. Census, the surname Grennan has seen a decline in popularity from 2000 to 2010. In 2000, the surname was ranked 25,825th in terms of popularity with a count of 895, translating to a proportion of 0.33 per 100,000 people. However, by 2010, the rank had slipped to 28,049 with a count of 854 and a proportion of 0.29 per 100,000 individuals, marking a decrease of 8.61% and 4.58%, respectively.

	2000	2010	Change
Rank	#25,825	#28,049	-8.61%
Count	895	854	-4.58%
Proportion per 100k	0.33	0.29	-12.12%

Race and Ethnicity of people with the last name Grennan

The Decennial U.S. Census data also provides insights into the changing ethnic identity associated with the surname Grennan. In 2000, the majority of those bearing the surname were of White ethnicity (95.87%), followed by those identifying as Two or More Races (1.34%) and Hispanic (1.23%); a small proportion identified as Asian/Pacific Islander (0.67%). By 2010, while the majority remained White (95.55%), there were notable increases in the proportions identified as Asian/Pacific Islander (rising to 1.17%) and Black (rising to 0.94%). The proportion of those identifying as Two or More Races also increased slightly to 1.52%. However, no individuals bearing the Grennan surname identified as Hispanic or American Indian and Alaskan Native in 2010.

	2000	2010	Change
White	95.87%	95.55%	-0.33%
Two or More Races	1.34%	1.52%	13.43%
Asian/Pacific Islander	0.67%	1.17%	74.63%
Black	0%	0.94%	0%
Hispanic	1.23%	0%	0%
American Indian and Alaskan Native	0%	0%	0%