| Kambja 260 borehole | Estonia | 58.2420, 26.7017 | 1 | 0 | 21 | 73 | |
| Kamariku borehole | Estonia | 59.0181, 26.2547 | 26 | 345 | 356 | 324 | |
| Kalvarija borehole | Lithuania | 54.4145, 23.2219 | 20 | 673 | 165 | 162 | |
| Kallemäe 828 borehole | Estonia | 58.3745, 22.9006 | 3 | 1 | 0 | 0 | |
| Kallavere F-119 borehole | Estonia | 59.4915, 25.0331 | 5 | 15 | 9 | 9 | |
| Kandava 25 borehole | Latvia | 57.0845, 22.7635 | 9 | 383 | 684 | 299 | |
| Kogula 1 borehole | Estonia | | 1 | 4 | 0 | 0 | |
| Kavastu 426 borehole (Tartumaa) | Estonia | 58.3805, 27.0788 | 11 | 1 | 25 | 117 | |
| Kipi borehole | Estonia | 58.2516, 22.0300 | 39 | 395 | 340 | 449 | |
| Kirikla F-304 borehole | Estonia | 59.1437, 24.5637 | 5 | 1 | 10 | 6 | |
| Kirikuküla borehole | Estonia | 58.7093, 23.7595 | 49 | 405 | 584 | 531 | |
| Kirikuküla F-160 borehole | Estonia | 59.2347, 26.4837 | 6 | 7 | 47 | 47 | |
| Kirila H-170 borehole | Estonia | 58.8625, 25.5715 | 3 | 1 | 0 | 0 | |
| Kirimäe F-350 borehole | Estonia | 58.9266, 23.7580 | 9 | 33 | 51 | 31 | |
| Kisuvere T-141 borehole | Estonia | 59.4167, 26.2890 | 7 | 2 | 38 | 35 | |
| Kiviloo F-282 borehole | Estonia | 59.2951, 25.2485 | 8 | 1 | 28 | 26 | |
| Kiviõli W-8 borehole | Estonia | 59.3591, 26.9592 | 1 | 2 | 58 | 6 | |
| Kloostri F-322 borehole | Estonia | 59.2202, 24.1422 | 3 | 0 | 13 | 13 | |
| Borehole No 1146, Leningrad Oblast | Russia | | 4 | 0 | 60 | 65 | |
| Koeravere F-157 borehole | Estonia | 59.2929, 26.3468 | 15 | 6 | 54 | 58 | |
| Kogula 704 borehole | Estonia | 58.2873, 22.2949 | 0 | 0 | 0 | 0 | |
| Kogula 985 borehole | Estonia | 58.2886, 22.2591 | 0 | 3 | 0 | 0 | |
| Kohila borehole | Estonia | 59.1676, 24.7308 | 7 | 1 | 171 | 170 | |
| Kohila 308 borehole | Estonia | 59.1753, 24.6201 | 6 | 2 | 51 | 49 | |
| Kohtla borehole | Estonia | 59.3804, 27.2671 | 1 | 2 | 80 | 0 | |
