I would like to thank my cousin, Paul Klein, for all of his research on the Korach family.  With the help of many relatives in the past 100 years, Paul has published a history of Leib Korach and his descendants. Here is a brief history of this family from his book published in 1994:

There are conflicting stories about Leib Korach.  Some say he was born in 1782, and come to Slovakia in 1795, while others say he came to Slovakia in 1782. From more than one source comes the story that whenever he did arrive in Slovakia, he overheard some German ethnic peasants in an inn, plotting to kill Count Csaky.  He reported the plot to the Count, it was foiled, and he was rewarded with a tract of land, which is in or near Siroka, Slovakia.  

Leib Korach was born in 1782 in Dukla, Galicia or Odessa, Russia??. He died in 1875 in Klukna, Hungary, now Kluknava, Slovakia, and buried at Siroka.  He married in 1810 to Rechel Pollak, (daughter of Yisrael Pollak and Leah ?), born in Nagy Vitez; died 3 October 1881 in Sumeg.  Leib and many of his children and grandchildren worked for and associated with the Count Csaky family (pronounced Chockie). Some of them were educated by the same tutors as the Csakys. Leib was a leader in the Jewish Community, and evidenced by a document Samuel Gross came across.  In the 1860s, the schism between Orthodox Jews and those advocating Reform finally led to the convocation of the Hungarian General Jewish Congress.  The Orthodox couldn't agree with the others, and in 1869 they petitioned for their own organization.  Leopold Korach is one of the 56 delegates on the official petition.  Leib and Rachel are buried at the Siroka, Slovakia graveyard.  

Their children were:

Wolf Korach, born 1811 .Married Leni Deutch. Lived in Mindszent.

Elias Korach,  died in 1901. Married Teibel Tannenbaum. Lived in Welbach.

Julka Korach, born 1821 in Siroka. Married Samuel Schwartz. Lived in Miskolc.

Haskell Korach, born 1823 in Siroka.  Married Lena Klein, born in 1826 in Presujfalu.  Then married Lena Engelman.

David Korach, born 1828. Married Gütel Weiss. Died in Miskolc in 1916.

Pinchas Korach, born 1826. Married Gizella Landau from Cracow. Lived in Kluknau.

Moritz Korach, born 1828 in Siroke. Died 22 January 1888 in Zsakarodz.  Married Hannah Pollacsek.

Lina Korach, Married Isaak Adler. Lived in Kassa.

Marie Korach, born 1836 in Siroka.  First married Abraham Samuel Horovitz and had seven children. Then married Rabbi Meyer Kohn and had three sons. Died in 1920 in Szepes Olaszi.

Israel Korach, born 1837 in Siroka. Died in 1913 in Szepes Olaszi. First married Miriam Bottenstein and had eight children.  Then married Rebecca Friedman Korach and had three more children.

Esther Korach, born 1839 in Siroka. Died in 1918 in Mad. Married Nathan Teitelbaum.

Simon Korach, born 1844 in Siroke Died in 1902. Married Rebecca Korach. Lived in Kotterbach.

Rebecca Korach, born 1845, married Ignac Friedman. Lived in Sumeg.