# Impact structures in Finland

As of June 2018, 12 confirmed impact structures have been found in Finland. They are listed below, sorted by original diameter.
List of identified impact structures in Finland :
| Structure name | Crater type | Diameter (km) | Diameter (km) | Depth (m) | Depth (m) | Depth (m) | Age (Myr) | Age (Myr) | Age (Myr) | Geologic period (epoch) | Location | Municipality | Impact origin shown [Note 3] | Notes |
| Structure name | Crater type | Original (estimate) [Note 1] | Current | Original (estimate) [Note 1] | Current (buried structure) | Current (solid surface) [Note 2] | Min | Max | Best fit | Geologic period (epoch) | Location | Municipality | Impact origin shown [Note 3] | Notes |
| Keurusselkä | Complex | 30 | 14 | 820 | | N/A | 1141 | 1161 | 1150 | Stenian | 62°07′49″N 24°37′58″E﻿ / ﻿62.1302°N 24.6327°E﻿ / 62.1302; 24.6327 | Keuruu / Mänttä-Vilppula | 2004 2010 | Heavily eroded, only remnants of central peak remain. |
| Lappajärvi | Complex | 20 | 17 | 730 | | 137 | 77.07 | 78.63 | 77.85 | Cretaceous (Late) | 63°08′40″N 23°39′03″E﻿ / ﻿63.1444°N 23.6508°E﻿ / 63.1444; 23.6508 | Lappajärvi / Alajärvi / Vimpeli | 1968 1970 1976 | Preserved well, rim outside lake largely intact. |
| Paasselkä | Complex? | | 10 | 590 | | 74 | 229.2 | 232.8 | 231.0 | Triassic (Late) | 62°09′18″N 29°24′03″E﻿ / ﻿62.1549°N 29.4008°E﻿ / 62.1549; 29.4008 | Savonlinna / Kitee | 1999 2003 2008 | Bay of Orivesi lake in Greater Saimaa. |
| Lumparn | Complex | 9 | 9 - 10 | 570 | | | 450 | 1250 | 580 | Ectasian to Ordovician | 60°08′34″N 20°07′17″E﻿ / ﻿60.1429°N 20.1215°E﻿ / 60.1429; 20.1215 | Jomala / Lemland / Lumparland / Sund | 1993 1997 | Bay of the Archipelago sea. |
| Söderfjärden | Complex, polygonal (hexagonal) | 6.6 | 6.6 | 520 | | 55 | 520 - 640 | | | Cambrian (Early) | 63°00′14″N 21°33′28″E﻿ / ﻿63.0039°N 21.5579°E﻿ / 63.0039; 21.5579 | Vaasa / Korsholm / Malax | 1978 1985 2013 | Extremely well preserved; rim nearly entirely intact, buried soon after impact, later exhumed. Dried bay of Kvarken. |
| Sääksjärvi | Simple? | 5 | 4.5 - 5 | 480 | | 9.1 | 544 | 576 | 560 | Ediacaran | 61°24′24″N 22°22′45″E﻿ / ﻿61.4066°N 22.3792°E﻿ / 61.4066; 22.3792 | Kokemäki | 1969 1980 1997 | Central part of the Sääksjärvi lake. |
| Suvasvesi N | Complex? | | 4 | 450 | | | 79.7 | 88.1 | 85 | Cretaceous (Late) | 62°39′11″N 28°10′43″E﻿ / ﻿62.6530°N 28.1786°E﻿ / 62.6530; 28.1786 | Kuopio / Leppävirta | 1995 1996 | Kukkarinselkä; open water in the Suvasvesi lake. |
| Suvasvesi S | Simple? Complex? | | ~4 | 450 | | | 679 | 727 | 710 | Cryogenian, possibly but unlikely Tonian | 62°35′33″N 28°12′51″E﻿ / ﻿62.5924°N 28.2143°E﻿ / 62.5924; 28.2143 | Kuopio / Leppävirta | 2001 2002 2003 | Haapaselkä; open water in the Suvasvesi lake. |
| Iso-Naakkima | Simple | < 4 | 2 - 3 | 450 - 600 | 160 | N/A | 900 | 1200 | | Stenian or Tonian | 62°12′08″N 27°07′31″E﻿ / ﻿62.2023°N 27.1252°E﻿ / 62.2023; 27.1252 | Pieksämäki / Mikkeli | 1993 | Buried, only partly under the Iso-Naakkima lake |
| Saarijärvi | Simple? | 3.4 | 1.5 - 2 | 420 | | | 0 | 541 | | Cambrian to Quaternary | 65°17′29″N 28°23′22″E﻿ / ﻿65.2915°N 28.3894°E﻿ / 65.2915; 28.3894 | Taivalkoski | 1997 1998 2013 | Central part of the Saarijärvi lake. |
| Summanen | Simple? | | 2.6 | 640 | 200 | 41 | 2.588 | 1910 | | Orosirian to Neogene | 62°38′52″N 25°22′42″E﻿ / ﻿62.6479°N 25.3782°E﻿ / 62.6479; 25.3782 | Saarijärvi | 2007 2018 | Central part of the Summanen lake. |
| Karikkoselkä | Simple | 3 | 1.3 | 640 | | 26 | 230 | 260 - 458 | | (Late) Ordovician to (Early) Triassic | 62°13′16″N 25°14′45″E﻿ / ﻿62.2212°N 25.2459°E﻿ / 62.2212; 25.2459 | Petäjävesi | 1996 1999 2000 | Open water in Petäjävesi lake |
Note 1: The "original" crater dimensions are coarse estimates. Original depths were calculated using the given original diameter using the Impact: Earth! program.
Note 2: "Current solid surface" topography is calculated from the deepest floor (regardless whether it is underwater or on dry land) to highest rim crest; other depth values give the depth of the floor in relation to the original terrain, thus excluding the rim and/or central uplift.
Note 3: Evidence for impact origin for a given structure is often provided in several publications. The year column includes some publications where some evidence of impact origin was provided even though an impact was not necessarily suggested by the authors; somewhere an impact was suggested even though the proof wasn't conclusive; and somewhere definite proof was provided.
General note 1: Crater sizes and shapes vary according to local differences. For example, depending on where you measure the crater diameter the result may vary (craters are seldom perfect circles). This is affected by, e.g., impact angle (low < 5-10 degree impact angles cause more elliptical craters) and local zones of weakness (may cause the crater to become polygonal).
General note 2: On Earth the (theoretical) transition diameter between simple and complex craters is 2 – 4 km. Such small craters may be either end member or some intermediate form, and thus the given dimension estimates may be off. The depth may be off by ~50 %.