The answer: Los Alamitos is an incorporated city; Rossmoor is an unincorporated community governed by the County of Orange, with a community services district for local services. Both use ZIP code 90720 and both are served by Los Alamitos Unified. Rossmoor homes sold for more over the three months ending September 2026: a median of $1,749,167 versus $1,471,799, and about $866 versus $712 per square foot.
Side by side
| Rossmoor | Los Alamitos | |
|---|---|---|
| Government | Unincorporated (County of Orange) + Rossmoor Community Services District | City of Los Alamitos, incorporated 1960 |
| ZIP code | 90720 | 90720 |
| School district | Los Alamitos Unified | Los Alamitos Unified |
| Housing | Mostly 1950s single-family, many remodeled | Single-family plus townhomes and condos |
| Median sale price | $1,749,167 | $1,471,799 |
| Price per sq ft | $866 | $712 |
| Median days on market | 35 | 76 |
| Sold above list | 34.5% | 25.0% |
Market figures: Redfin, three months ending September 2026.
Why it matters when you buy
- Rules and permits. A remodel in Rossmoor goes through the County; in Los Alamitos, through the city.
- Services. Parks, recreation and street trees in Rossmoor come from the Rossmoor Community Services District.
- Housing stock. Rossmoor is nearly all single-family homes, so it rarely offers a lower-cost entry point; Los Alamitos sometimes does, through townhomes and condos.
How to tell which one a home is in
The mailing address won't tell you, since both say "Los Alamitos, CA 90720." Check the property's tax record or the County's parcel information, or ask Eunice to confirm before you write an offer.