| KACPRZAK | Krakow | 1891 | | | NY | 1908 |
| KACZMARCZYK | Jergarka | | | | | |
| KADZIOLKI | Rzeszowski | | Mielec | | | |
| KAESER | Wroclaw | 1800 | | | | |
| KALBUS | Gramewz | 1700-1865 | Poznan | Winnebago | WI | 1864 |
| KALICINSKI | Lublin | 1800 | | | | |
| KALITA | Lublin | 1800 | | | | |
| KALLAS | Germ-Poland | 1855 | | Benton | MN | |
| KALLAS | Germany | 1815 | Bonnissia | Benton | MN | |
| KALUPA | | | | | WI | 1871 |
| KALZOR | Krosno | | | | | |
| KAMEDULSKI | | | | Marquette | WI | 1900 |
| KAMINSKA | Polish
Russia | 1906 | | Hillsborough | NH | 1906 |
| KAMINSKI | Prussia | 1872 | | | | |
| KANNENBERG | Poznan | 1870 | | | | |
| KAPCHINSKI | Poznan | 1870-1996 | | Brazos | TX | 1870-1996 |
| KAPCZINSKI | Poznan | 1870-1996 | | Brazos | TX | 1870-1996 |
| KAPCZYNSKI | Poznan | 1870-1996 | | Brazos | TX | 1870-1996 |
| KAPPA | Poznan | 1870-1996 | | Brazos | TX | 1870-1996 |
| KARAS | | 1900's | Mielec | | | |
| KARAS | | 1900's | | | | |
| KARASIEWICZ | Droniczyn | | | | | |
| KARASINSKI | Rzeszow | 1820-1910 | Jaslo | | | |
| KARPOWICZ | Vilno | | Wilejski | Allegheny | PA | 1913 |
| KARPOWICZ | Vilno | | Wilejski | Cuyahoga | OH | 1922 |
| KASER | Wroclaw | 1800 | | | | |
| KASPRZAK | Krakow | 1891 | | | NY | 1908 |
| KATARSKI | Myszyniec | <
1905 | | | IL | 1886 |
| KATORA | Prussia | | | | IL | 1882 |
| KATORSKI | Myszyniec | <
1905 | | | IL | 1886 |
| KAVA | Tarnow | 1900-1925 | | | NE | |
| KAWA | Tarnow | 1900-1925 | | | NE | |
| KAWCZYNSKI | Russia | 1912-1996 | | | NY | |
| KAZUBSKA | | | | | | |
| KERPCHAR | | 1700-1900 | | | | |
| KIELIJAN | Bydgoszcz | 1874 | | | | |
| KIERPCHAR | | 1700-1900 | | | | |
| KIERPCZAR | Poland | 1700-1900 | | | | |
| KIRKOWSKI | Poland | | | Benton | MN | |
| KISIEL | Galicia | 1800- | Tarnow | | | |
| KISKIEWICZ | Droniczyn | | | | | |
| KLEMECKI | Kutno | 1867 | | | OH | |
| KLEMENT | Lodz | 1867 | Krosniewice | | | |
| KLENIEWSKI | Warszawskie | 1840 | Pultusk | | | |
| KLOSOWSKI | | | | Hudson | NJ | 1908 |
| KLUZIK | Tarnow | 1765 | | | | |
| KMIECIEWICZ | Poznan | 1800 | Oborniki | | | |
| KOBANY | Rzeszow | 1857 | Mielec | | | |
| KOCH | East
Prussia | | | | | |
| KOCHAN | Tarnow | 1793 | | | | |
| KOCURZGKA | Tarnow | 1791 | | | | |
| KOCZOR | Tarnow | 1865 | | | | |
| KOJICKA | Zamosc | | | | | |
| KOLANKOWSKI | Ciechanow | 1900 | Lekowo | Passaic | NJ | 1900-1934 |
| KOLODZIEJ | Galicia | 1750-1860 | Rzeszow | Hampshire | MA | 1888 |
| KOLODZIEJCZYK | Galicia | 1750-1860 | Rzeszow | Hampshire | MA | 1888 |
| KONARSKI | Krakow | | | | | |
| KONCAK | Kepno | 1600-1996 | | | | |
| KONCZAK | Warsaw | 1600-1996 | | | | |
| KONCZAK | Usch | 1600-1996 | | | | |
| KONCZAK | | 1600-1996 | | | | |
| KONCZAKOWSCY | New
Russia | 1600 | | | | |
| KONCZAKOWSKI | Old
Poland | 1600 | | | | |
| KONCZAKOWSKI | New
Russia | 1600 | | | | |
| KONICKI | Galicia | 1750-1860 | Rzeszow | | | |
| KONIECZKO | Krosno | 1880 | | | | |
| KONWOW | Lublin | 1800 | | | | |
| KONZAK | Lodz | 1600-1996 | | | | |
| KOOZELNIK | | | | | | |
| KOPROWSKI | Warsaw | 1870 | | Allegheny | PA | 1890 |
| KOPROWSKI | Warsaw | 1870 | | Cuyahoga | OH | 1920 |
| KORTNETSKI | Prussia | | | | WI | |
| KOSTRUBALA | Lublin | 1754 | | Cook | IL | 1913 |
| KOSTYROK | Silesia | | | | | |
| KOTARSKI | Myszyniec | <
1905 | | | IL | 1886 |
| KOTULYA | Slovakia | 1700-1800 | | | | |
| KOWALEWSKA | Poznan | 1833-1882 | | Manistee | MI | 1882-1905 |
| KOWALZEK | | | | | | |
| KOWNACKI | Olsztyn | 1800 | Nidzica | | | |
| KOWR | Tarnow | 1801 | | | | |
| KOWRZONKA | Tarnow | 1801 | | | | |
| KOZAK | Tarnow | 1863 | Brzeska | | | |
| KOZIELSKI | Russia-Poland | 1800-1996 | Lidzianka | | | |
| KOZIK | Poland | 1794 | | | | |
| KOZIKOWNA | Tarnow | 1801 | | | | |
| KOZLOWSKI | Bialystok | 1870 | | Cook | IL | 1898 |
| KRAJEWSKA | Pilichowo | | | | | |
| KREMIN | Sachaczew | 1865 | | | | |
| KREMSKA | | | | | | 1900 |
| KRISAK | Aust/Hungary | | | | | |
| KROCHMAL | Galicia | 1750-1860 | Rzeszow | | | |
| KROL | Minsk
Mazowiecki | | | | | |
| KROL | Krakow | 1850-1920 | | | IL | |
| KROTKIEWICZ | Zamosc | | | | MI | |
| KROZ | Rzeszowski | | | | | |
| KRUCENA | Galicia | 1750-1860 | Rzeszow | Hampshire | MA | 1888 |
| KRUGER | Sachaczew | 1850 | | | | |
| KRUK | Tarnow | 1856 | | | | |
| KRUSZYNA | Galicia | 1750-1860 | Rzeszow | Hampshire | MA | 1888 |
| KRYGER | Sachaczew | 1850 | | | | |
| KRZYWDZIK | Krosno | 1700-1900 | | | | |
| KRZYWONOS | Przemysl | 1800-1850 | Jaroslaw | | | |
| KUBAS | Przemysl | 1800-1850 | Jaroslaw | | | |
| KUCHARSKI | | 1850 | Zamosc | | | |
| KUCYBA | Galicia | 1889 | | | | |
| KUKA | | | | | | |
| KULBABA | Ivano-Frankivsk | 1800-1996 | Ukraine | | | |
| KULMA | Krakow | 1850-1920 | | | | |
| KULVICKI | | | | Hudson | NJ | 1906 |
| KULWICKI | Torun | 1888 | Rypin | | | |
| KULWICKI | Torun | 1959 | Rypin | | | |
| KULWICKI | Torun | 1902 | Rypin | | | |
| KULWICKI | Torun | 1911 | Rypin | | | |
| KULWICKI | Torun | 1905 | Brodnica | | | |
| KURZAWA | Poznan | 1871 | | | | |
| KURZYNOWSKI | Warsaw | 1800 | | | | |
| KUSTRON | Brzozow | | | | | 1900 |
| KUSY | Lublin | 1795 | | | | |
| KUT | Galicia | 1750-1860 | Rzeszow | | | |
| KUTSERA | Slovakia | 1700-1800 | | | | |
| KWIATKOWSKI | Lodz | 1869 | Krosniewice | | | |
| KWIEK | Tarnow | 1801 | | | | |
| KWOKOW | Lublin | 1798 | | | | |
|