| Kohtla 7 borehole | Estonia | 59.3544, 27.2128 | 3 | 41 | 114 | 19 | |
| Kohtla-Järve borehole | Estonia | 59.3948, 27.2584 | 0 | 0 | 0 | 0 | |
| Koigi 775 borehole | Estonia | 58.4912, 23.0188 | 0 | 0 | 0 | 0 | |
| Kõiguste 833 borehole | Estonia | 58.3731, 22.9795 | 5 | 7 | 39 | 82 | |
| Koikla 821 borehole | Estonia | 58.4777, 22.7714 | 0 | 0 | 0 | 0 | |
| Koimla 560 borehole | Estonia | 58.2129, 22.1386 | 0 | 0 | 0 | 0 | |
| Kõinastu 540 borehole | Estonia | 58.6433, 23.0267 | 2 | 10 | 15 | 4 | |
| Koki 879 borehole | Estonia | 58.2446, 22.1098 | 0 | 0 | 0 | 0 | |
| Koki 983 borehole | Estonia | 58.2416, 22.0739 | 0 | 0 | 0 | 0 | |
| Koela F-348 borehole | Estonia | 58.9805, 23.7432 | 3 | 0 | 41 | 49 | |
| Kybartai 33 borehole | Lithuania | | 0 | 2 | 0 | 0 | |
| Keila 117 borehole | Estonia | 59.3086, 24.3921 | 10 | 0 | 56 | 31 | |
| Keila 30a borehole | Estonia | 59.3114, 24.4341 | 1 | 0 | 1 | 0 | |
| Keila 8 borehole | Estonia | | 1 | 4 | 0 | 0 | |
| Keila quarry borehole | Estonia | 59.3138, 24.3784 | 3 | 0 | 132 | 59 | |
| Kemba F-116 borehole | Estonia | 59.4694, 25.7030 | 6 | 0 | 275 | 275 | |
| Kemeri-Loku 580 borehole | Estonia | 58.1601, 26.6389 | 3 | 0 | 0 | 0 | |
| Kerema K170 borehole | Estonia | 58.8993, 22.9527 | 0 | 1 | 0 | 0 | |
| Kerguse 743 borehole | Estonia | 58.2976, 22.4413 | 0 | 0 | 0 | 0 | |
| Keri 258 borehole | Estonia | 58.3297, 26.4799 | 1 | 0 | 16 | 36 | |
| Keskranna 798 borehole | Estonia | 58.4324, 22.0661 | 1 | 0 | 0 | 0 | |
| Kestla 248 borehole | Estonia | 59.4197, 26.9041 | 13 | 4 | 4 | 3 | |
| Ketrzyn IG 1 borehole, Poland | Poland | 54.0766, 21.3750 | 5 | 98 | 46 | 46 | |
| Kioma 291 borehole | Estonia | 58.0361, 26.9514 | 7 | 3 | 62 | 163 | |
| Kybartai 29 borehole | Lithuania | | 1 | 819 | 457 | 89 | |
