| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Obecuri | city | Castilla y Leon | Spain | 42.65 | -2.53 | 2509 | 547 |
| Obekuri | city | Castilla y Leon | Spain | 42.65 | -2.53 | 2509 | 547 |
| Oblanca | city | Castilla y Leon | Spain | 42.92 | -5.88 | 4399 | 313 |
| Occilis | city | Castilla y Leon | Spain | 41.17 | -2.43 | 3349 | 294 |
| Oceja de Valdellorma | city | Castilla y Leon | Spain | 42.81 | -5.20 | 3694 | 1741 |
| Ocejo de la Peña | city | Castilla y Leon | Spain | 42.86 | -5.09 | 5065 | 2019 |
| Ocellum Duri | city | Castilla y Leon | Spain | 41.50 | -5.75 | 1975 | 52381 |
| Ocenilla | city | Castilla y Leon | Spain | 41.80 | -2.62 | 3480 | 2092 |
| Ocero | city | Castilla y Leon | Spain | 42.70 | -6.63 | 3349 | 3116 |
| Ochando | city | Castilla y Leon | Spain | 41.05 | -4.44 | 2926 | 810 |
| Ocilla | city | Castilla y Leon | Spain | 42.76 | -2.78 | 2509 | 10757 |
| Oco | city | Castilla y Leon | Spain | 40.63 | -4.97 | 4255 | 744 |
| Ocon de Villafranca | city | Castilla y Leon | Spain | 42.40 | -3.31 | 3349 | 436 |
| Odollo | city | Castilla y Leon | Spain | 42.35 | -6.59 | 2910 | 277 |
| Oencia | city | Castilla y Leon | Spain | 42.55 | -6.97 | 3349 | 625 |
| Ogeta | city | Castilla y Leon | Spain | 42.71 | -2.65 | 2037 | 310 |
| Ogueta | city | Castilla y Leon | Spain | 42.71 | -2.65 | 2037 | 310 |
| Ojeda | city | Castilla y Leon | Spain | 42.76 | -3.51 | 2509 | 505 |
| Ojos-Albos | city | Castilla y Leon | Spain | 40.71 | -4.52 | 4566 | 1715 |
| Ojuel | city | Castilla y Leon | Spain | 41.72 | -2.28 | 3349 | 348 |
| Olea de Boedo | city | Castilla y Leon | Spain | 42.61 | -4.45 | 3349 | 458 |
| Oleo | city | Castilla y Leon | Spain | 43.00 | -3.32 | 2549 | 1177 |
| Olivares de Duero | city | Castilla y Leon | Spain | 41.64 | -4.37 | 2509 | 1337 |
| Olleros | city | Castilla y Leon | Spain | 41.98 | -6.10 | 2509 | 1286 |
| Olleros | city | Castilla y Leon | Spain | 40.79 | -6.07 | 2765 | 489 |
| Olleros de Alba | city | Castilla y Leon | Spain | 42.80 | -5.70 | 3576 | 2866 |
| Olleros de Paredes Rubias | city | Castilla y Leon | Spain | 42.78 | -4.01 | 2572 | 296 |
| Olleros de Pisuerga | city | Castilla y Leon | Spain | 42.74 | -4.29 | 3349 | 2344 |
| Olleros de Sabero | city | Castilla y Leon | Spain | 42.83 | -5.18 | 3648 | 2376 |
| Olleros de Tera | city | Castilla y Leon | Spain | 41.98 | -6.10 | 2509 | 1286 |
| Olmedilla | city | Castilla y Leon | Spain | 40.77 | -5.86 | 3349 | 633 |
| Olmedillo de Roa | city | Castilla y Leon | Spain | 41.78 | -3.93 | 2693 | 818 |
| Olmedo | city | Castilla y Leon | Spain | 41.29 | -4.69 | 2509 | 1672 |
| Olmedo de Camaces | city | Castilla y Leon | Spain | 40.88 | -6.62 | 2509 | 497 |
| Olmillo | city | Castilla y Leon | Spain | 41.32 | -3.69 | 3349 | 722 |
| Olmillos | city | Castilla y Leon | Spain | 41.53 | -3.16 | 2933 | 910 |
| Olmillos de Castro | city | Castilla y Leon | Spain | 41.73 | -5.97 | 2509 | 641 |
| Olmillos de Muno | city | Castilla y Leon | Spain | 42.20 | -3.94 | 2637 | 819 |
| Olmillos de Sasamon | city | Castilla y Leon | Spain | 42.40 | -4.03 | 2723 | 1114 |
| Olmillos de Valverde | city | Castilla y Leon | Spain | 41.91 | -5.76 | 2509 | 1735 |
| Olmo de la Guareña | city | Castilla y Leon | Spain | 41.16 | -5.31 | 2509 | 1027 |
| Olmos de Atapuerca | city | Castilla y Leon | Spain | 42.39 | -3.53 | 3349 | 1130 |
| Olmos de Esgueva | city | Castilla y Leon | Spain | 41.69 | -4.52 | 2509 | 579 |
| Olmos de Ojeda | city | Castilla y Leon | Spain | 42.72 | -4.42 | 3349 | 705 |
| Olmos de Penafiel | city | Castilla y Leon | Spain | 41.57 | -4.04 | 2631 | 2129 |
| Olmos de Pisuerga | city | Castilla y Leon | Spain | 42.48 | -4.27 | 2611 | 1605 |
| Olmos de la Picaza | city | Castilla y Leon | Spain | 42.48 | -4.03 | 2696 | 672 |
| Olmosalbos | city | Castilla y Leon | Spain | 42.24 | -3.67 | 2893 | 2396 |
| Olombrada | city | Castilla y Leon | Spain | 41.41 | -4.16 | 2824 | 1126 |
| Olvega | city | Castilla y Leon | Spain | 41.78 | -1.98 | 3431 | 2426 |
| Omañón | city | Castilla y Leon | Spain | 42.81 | -6.10 | 4189 | 304 |
| Omenaca | city | Castilla y Leon | Spain | 41.76 | -2.24 | 3602 | 208 |
| Ona | city | Castilla y Leon | Spain | 42.73 | -3.41 | 2578 | 877 |
| Onamio | city | Castilla y Leon | Spain | 42.56 | -6.50 | 2509 | 6359 |
| Oncala | city | Castilla y Leon | Spain | 41.97 | -2.31 | 4416 | 224 |
| Oncina de la Valdoncina | city | Castilla y Leon | Spain | 42.55 | -5.66 | 2837 | 21413 |
| Ontalbilla de Valcorba | city | Castilla y Leon | Spain | 41.76 | -2.37 | 3441 | 1856 |
| Ontalvilla de Valcorba | city | Castilla y Leon | Spain | 41.76 | -2.37 | 3441 | 1856 |
| Onzonilla | city | Castilla y Leon | Spain | 42.52 | -5.58 | 2604 | 36164 |
| Opio | city | Castilla y Leon | Spain | 43.14 | -3.23 | 1217 | 3338 |
| Oquillas | city | Castilla y Leon | Spain | 41.83 | -3.71 | 3349 | 349 |
| Orallo | city | Castilla y Leon | Spain | 42.97 | -6.35 | 4189 | 6450 |
| Orbananoz | city | Castilla y Leon | Spain | 42.75 | -3.18 | 2509 | 568 |
| Orbaneja del Castillo | city | Castilla y Leon | Spain | 42.84 | -3.79 | 2769 | 126 |
| Orbaneja-Ríopico | city | Castilla y Leon | Spain | 42.36 | -3.59 | 3349 | 34936 |
| Orbita | city | Castilla y Leon | Spain | 41.00 | -4.65 | 2854 | 1399 |
| Orbo | city | Castilla y Leon | Spain | 42.88 | -4.26 | 4189 | 2179 |
| Ordejon de Arriba | city | Castilla y Leon | Spain | 42.63 | -4.05 | 3484 | 333 |
| Ordejón de Abajo | city | Castilla y Leon | Spain | 42.64 | -4.07 | 3349 | 297 |
| Ordejón de Abajo o Santa Maria | city | Castilla y Leon | Spain | 42.64 | -4.07 | 3349 | 297 |
| Ordono | city | Castilla y Leon | Spain | 41.20 | -5.30 | 2608 | 828 |
| Orellán | city | Castilla y Leon | Spain | 42.47 | -6.75 | 2509 | 1852 |
| Orillares | city | Castilla y Leon | Spain | 41.79 | -3.21 | 3349 | 433 |
| Orones | city | Castilla y Leon | Spain | 42.96 | -5.24 | 4245 | 773 |
| Ortigos de Pestano | city | Castilla y Leon | Spain | 41.09 | -4.40 | 2906 | 764 |
| Ortigosa de Pestano | city | Castilla y Leon | Spain | 41.09 | -4.40 | 2906 | 764 |
| Ortigosa de Rioalmar | city | Castilla y Leon | Spain | 40.67 | -5.05 | 4189 | 545 |
| Ortigosa de Tormes | city | Castilla y Leon | Spain | 40.37 | -5.30 | 5160 | 299 |
| Ortigosa del Monte | city | Castilla y Leon | Spain | 40.84 | -4.18 | 3700 | 3813 |
| Ortigosa del Ríoalmar | city | Castilla y Leon | Spain | 40.67 | -5.05 | 4189 | 545 |
| Orzonaga | city | Castilla y Leon | Spain | 42.85 | -5.54 | 3576 | 2494 |
| Orón | city | Castilla y Leon | Spain | 42.67 | -2.98 | 1669 | 27175 |
| Os Mazos | city | Castilla y Leon | Spain | 42.57 | -6.90 | 2509 | 1110 |
| Oseja de Sajambre | city | Castilla y Leon | Spain | 43.14 | -5.04 | 2936 | 424 |
| Osma | city | Castilla y Leon | Spain | 41.58 | -3.08 | 3349 | 1603 |
| Osona | city | Castilla y Leon | Spain | 41.58 | -2.73 | 3349 | 360 |
| Osonilla | city | Castilla y Leon | Spain | 41.60 | -2.67 | 3349 | 582 |
| Osornillo | city | Castilla y Leon | Spain | 42.37 | -4.29 | 2539 | 1219 |
| Osorno | city | Castilla y Leon | Spain | 42.41 | -4.36 | 2591 | 1534 |
| Osorno la Mayor | city | Castilla y Leon | Spain | 42.41 | -4.36 | 2591 | 1534 |
| Oteo | city | Castilla y Leon | Spain | 43.00 | -3.32 | 2549 | 1177 |
| Oter de Bodas | city | Castilla y Leon | Spain | 41.94 | -6.15 | 2654 | 774 |
| Oterico | city | Castilla y Leon | Spain | 42.78 | -5.92 | 3556 | 880 |
| Otero | city | Castilla y Leon | Spain | 41.94 | -6.15 | 2654 | 774 |
| Otero | city | Castilla y Leon | Spain | 42.57 | -6.78 | 1669 | 6083 |
| Otero | city | Castilla y Leon | Spain | 42.54 | -6.60 | 1748 | 37627 |
| Otero Vaciadores | city | Castilla y Leon | Spain | 40.88 | -5.77 | 2788 | 858 |
| Otero de Bodas | city | Castilla y Leon | Spain | 41.94 | -6.15 | 2654 | 774 |
| Otero de Bodos | city | Castilla y Leon | Spain | 41.94 | -6.15 | 2654 | 774 |
| Otero de Centenos | city | Castilla y Leon | Spain | 42.05 | -6.32 | 2896 | 615 |
| Otero de Curueno | city | Castilla y Leon | Spain | 42.86 | -5.40 | 3595 | 759 |
| Otero de Escarpizo | city | Castilla y Leon | Spain | 42.52 | -6.06 | 2818 | 3615 |
| Otero de Guardo | city | Castilla y Leon | Spain | 42.88 | -4.81 | 4189 | 936 |
| Otero de Herreros | city | Castilla y Leon | Spain | 40.82 | -4.21 | 4189 | 3012 |
| Otero de María Asensio | city | Castilla y Leon | Spain | 40.88 | -5.55 | 2847 | 5485 |
| Otero de Naraguantes | city | Castilla y Leon | Spain | 42.77 | -6.61 | 3349 | 6717 |
| Otero de Sanabria | city | Castilla y Leon | Spain | 42.05 | -6.57 | 3349 | 1225 |
| Otero de Sariegos | city | Castilla y Leon | Spain | 41.82 | -5.61 | 2509 | 966 |
| Otero de las Duenas | city | Castilla y Leon | Spain | 42.79 | -5.77 | 3553 | 903 |
| Oteros de Boedo | city | Castilla y Leon | Spain | 42.66 | -4.49 | 3349 | 504 |
| Oteruelo | city | Castilla y Leon | Spain | 42.42 | -6.09 | 2883 | 6866 |
| Oteruelo de la Valdoncina | city | Castilla y Leon | Spain | 42.58 | -5.60 | 2693 | 130343 |
| Oteruelo de la Valduerna | city | Castilla y Leon | Spain | 42.42 | -6.09 | 2883 | 6866 |
| Oteruelo de la Vega | city | Castilla y Leon | Spain | 42.36 | -5.88 | 2555 | 4507 |
| Oteruelos | city | Castilla y Leon | Spain | 41.84 | -2.60 | 3562 | 2722 |
| Otones | city | Castilla y Leon | Spain | 41.14 | -4.06 | 3349 | 968 |
| Otones de Benjumea | city | Castilla y Leon | Spain | 41.14 | -4.06 | 3349 | 968 |
| Ovilla | city | Castilla y Leon | Spain | 43.09 | -3.26 | 1765 | 404 |
| Oville | city | Castilla y Leon | Spain | 42.91 | -5.35 | 4189 | 935 |
| Ozana | city | Castilla y Leon | Spain | 42.71 | -2.79 | 2536 | 613 |
| Ozilla | city | Castilla y Leon | Spain | 42.76 | -2.78 | 2509 | 10757 |
| Ozuela | city | Castilla y Leon | Spain | 42.50 | -6.62 | 2509 | 24123 |