Agat's 2026 population is now estimated at 4,290. In 1990, the population of Agat was 4,960. Agat experienced a decrease of -37 residents over the past year, marking an annual decline of -0.86%. These population values and projections come from Guam BSP decennial municipality population table (1990-2010), U.S. Census Bureau 2020 Island Areas Guam DHC municipality population and World Population Review Internal Projections .
| City | 2026 Pop. ↓ | Growth |
|---|---|---|
| Dededo | 44,887 | -0.01% |
| Yigo | 18,653 | -0.6% |
| Tamuning | 17,807 | -0.63% |
| Mangilao | 12,541 | -1.2% |
| Barrigada | 7,451 | -1.09% |
| Chalan Pago-Ordot | 7,213 | 0.35% |
| Santa Rita | 6,713 | 0.61% |
| Yona | 6,191 | -0.29% |
| Mongmong-Toto-Maite | 6,127 | -0.68% |
| Agat | 4,290 | -0.86% |
| Talofofo | 3,888 | 1.51% |
| Agana Heights | 3,594 | -0.36% |
| Sinajana | 2,622 | 0.04% |
| Inarajan | 2,344 | 0.21% |
| Asan | 1,939 | -0.62% |
| Piti | 1,669 | 0.85% |
| Merizo | 1,472 | -1.47% |
| Hagatna | 884 | -1.01% |
| Umatac | 578 | -1.87% |
