The O'BRIEN surname in the USA

Frequency Comparisons
	Total	Rank	Frequency %	Per million people
United States
United States (Current snapshot)	115,385	234	0.043	428
United States (1880 census)	9,707	623	0.019	194
Change since 1880	+105678	+389	+0.024	+234
Other Countries
Australia	474	3368	0.003	29
United Kingdom	3,098	2006	0.007	67

Top States for O'BRIEN by Total
State	Total	Rank in State	Frequency %	Per million people
New York	11,482	70	0.061	605
Massachusetts	11,042	16	0.174	1,739
California	9,551	286	0.028	282
Florida	7,472	208	0.047	468
Pennsylvania	6,236	128	0.051	508
Top States for O'BRIEN by Frequency
State	Total	Rank in State	Frequency %	Per million people
Massachusetts	11,042	16	0.174	1,739
New Hampshire	1,442	42	0.117	1,167
Vermont	692	49	0.114	1,137
Rhode Island	1,002	48	0.096	956
Connecticut	3,102	47	0.091	911

Notes

Total is the total number of people with that surname.
Rank is the position in the list of names ordered by total (eg, a rank of 1 means that it's the most common name, and a rank of 10 means it's the tenth most common, etc).
Frequency is the percentage of people with that surname.
Per million people is the number of people with that surname per million of the population.

'A figure of zero indicates that we don't have data for this name (usually because it's quite uncommon and our stats don't go down that far). It doesn't mean that there's no-one with that name at all!

For less common surnames, the figures get progressively less reliable the fewer holders of that name there are. This data is aggregated from several public lists, and some stats are interpolated from known values. The margin of error is well over 100% at the rarest end of the table!

For less common surnames, the frequency and "per million" values may be 0 even though there are people with that name. That's because they represent less than one in a million of the population, which ends up as 0 after rounding.

It's possible for a surname to gain in rank and/or total while being less common per million people (or vice versa) as there are now more surnames in the USA as a result of immigration. In mathematical terms, the tail has got longer, with a far larger number of less common surnames.

Figures for top states show firstly the states where most people called O'BRIEN live. This obviously tends to be biased towards the most populous states. The second set of figures show where people called O'BRIEN represent the biggest proportion of the population. So, in this case, there are more people called O'BRIEN in New York than any other state, but you are more likely to find a O'BRIEN by picking someone at random in Massachusetts than anywhere else.

Classification and Origin of O'BRIEN

Region of origin: British Isles

Country of origin: Ireland

Language of origin: Gaelic

Ethnic origin: Celtic

Religious origin: Christian

Name derivation: From name of parent

Data for religion and/or language relates to the culture in which the O'BRIEN surname originated. It does not necessarily have any correlation with the language spoken, or religion practised, by the majority of current American citizens with that name.

Data for ethnic origin relates to the region and country in which the O'BRIEN surname originated. It does not necessarily have any correlation with the ethnicity of the majority of current American citizens with that name.

Ethnic distribution of O'BRIEN in the USA

Classification	Total	Percent
Asian/Pacific	612	0.53
Native American/Alaskan	381	0.33
White (Caucasian)	109,973	95.31
Black/African American	1,304	1.13
Mixed Race	1,362	1.18
White (Hispanic)	1,754	1.52

Ethnic distribution data shows the number and percentage of people with the O'BRIEN surname who reported their ethnic background as being in these broad categories in the most recent national census.

Similar names to O'BRIEN

The following names have similar spellings or pronunciations as O'BRIEN.

This does not necessarily imply a direct relationship between the names, but may indicate names that could be mistaken for this one when written down or misheard.