Seamus ranks at #591 with 208 entries, registered male. The name is the Irish form of James, with a pronunciation that catches non-Irish-speakers off-guard: SHAY-mus, with a soft Sh-opening that the spelling does not signal. On a pet, the name almost always reads as a deliberate Irish-heritage choice rather than a casual phonetic pick.
The Irish-heritage cohort
Seamus sits with Finn, Murphy, Riley, and Fiona in the same naming pocket — Irish-derived names that American owners deploy as a heritage signal or as a bookish sound-preference choice. The cohort is concentrated in Irish-American households and in cities with strong Irish cultural lineage (Boston, Chicago, NYC), but spreads well beyond that core through literary and musical channels.
Breed lean
The name lands disproportionately on Irish breeds and Irish-coded breeds — Irish Wolfhounds, Irish Setters, Irish Terriers, and any reddish-coated dog where the breed-name match reinforces the heritage signal. Labradors, particularly red-coat Labs, also wear the name well. Smaller breeds wear it less often; the name has a wolfhound-shaped weight to it.
The pronunciation hurdle
Worth flagging the pronunciation issue. The Irish-spelling-versus-English-phonetics gap (SHAY-mus, not SEE-mus) means owners spend the dog's first year correcting groomers, vets, and dog-park strangers. Most settle into a relaxed acceptance of the variation. The Seamus baby name page shows steady SSA presence in Irish-American naming patterns.