The participants in the Horn/Horne Project have been placed in specific groups based on their Y-DNA results:

(NOTE: The earliest known ancestor for each group is noted below.)
 
Horn Group 1:  (38 members)  Richard Horn, born before 1716 and died 1779, Halifax County, NC. Other ancestors are Ephraim Horn, born in 1734, Sherrod Horn, born 1760, and William Horn, born 1768. This group includes 6 members with the surname of McEntire.
 
Horn Group 2:  (8 members)  Henry Horn, born 1716 and died 1798. Two men with the last name of Hunt are also members of this group. One may consider that the Horn and Hunt members in this group most likely shared a common ancestor sometime in the past. This leads to the following questions: Was this common ancestor named Horn or was he named Hunt? When did the Non Paternal Event occur? 
 
Horn Group 3:  (20 members)  William Horn, born 1690 in Virginia. Other ancestors are Jesse Horn, and Elijah Horne.
 
Horn Group 4:  (9 members)  Thomas Horn Sr., born about 1725 in Maryland. Other ancestors are James Horn, born 1818 in Highland County, OH, and William R. Horn, born 1830 in Tennessee. 
 
Horn Group 5:  (2 members)  Thomas Horn, born 1720 Nansemond County, VA. The other ancestor is Michael Jordan Horne, born 1815 in Georgia. 
 
Horn Group 6:  (6 members)  Phillip Horn of Tennessee. Other ancestors are Frederick Horn, born 1780 in England, Thomas Horn, born 1858 in West Virginia, and Anthony Horn, born 1777 in Virginia. 
 
Horn Group 7:  (2 members)  Jesse Horn, born about 1783 in Pennsylvania. 
 
Horn Group 8A:  (6 members)  Christopher Horn, born 1745 in Pennsylvania. 
 
Horn Group 8B:  (2 members)  The earliest known ancestor of this group is also believed to have been Christopher Horn, born 1745 in Pennsylvania, just like the two members of Group 8A. They are perfect matches and do not match closely with the two members of Group 8A.  
 
Horn Group 9:  (1 member)  Joshua Horn, born 1796 in North Carolina. This member doesn't match with any other member of the Horn/Horne Project. Another member of the Horn/Horne Project claims to be a descendant of Joshua Horn, born 1796 in North Carolina. He matches with the other members of Horn Group 1. 
 
Horn Group A:  (5 members)  Johann Kroft Horn, born 1690/1696 in Westphalia, Germany. Also Charles Horn I, and Aaron Horn, born 1740, and died 1778.
 
Horn Group AA:  (2 members)  Peter Horn, born 1886 and died 1975.
 
Horn Group B:  (2 members)  Sivender Horn and Winslow Wilkins Horne. 
 
Horn Group BB:  (7 members)  Christoph Horn, born about 1695/96 in Eichel, Baden, Germany. Other ancestors are John Peter Horn who died in 1759 and was buried in Northampton County, Pennsylvania, Jacob Horn, born about 1768 in Maryland and died after 1850 probably in Bledsoe County,TN, and Joseph Horn, born 1791 Pennsylvania or New Jersey, died 1861 Northampton County, PA. 
 
Horn Group C1:  (1 member)  Herszla Horn, born 1755 Polaniec, Poland. This member doesn't match with any other member of the Horn/Horne DNA Project. The members of Group's C1 and C2 are the only members of the Horn/Horne DNA Project who are designated as Haplogroup J.
 
Horn Group C2:  (1 member)  Philipp Horn. This member doesn't match with any other member of the Horn/Horne DNA Project. The members of Group's C1 and C2 are the only members of the Horn/Horne DNA Project who are designated as Haplogroup J. 
 
Horn Group CC:  (1 member)  Charles Horn, born 1845 in Missouri. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group D:  (1 member)  Nicholas Horn, born 1814 in Tennessee. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group DD:  (1 member)  John George Horn, born 1775 Maryland and died 1859 in Tennessee. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group E:  (4 members)  William Van Horn, born about 1769, and Samuel A. Horn, born 1829 in Lehigh County, Pennsylvania.
 
Horn Group EE:  (2 members)  Joseph Henry Horne, born 1845 in England. The ancestor for the other member is unknown.
 
Horn Group F:  (1 member)  Lewis Horn, born 1875 in Germany. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group FF:  (1 member)  George Horn, born 1756 in Martinsburg, Berkeley County, VA.
 
Horn Group G:  (1 member)  Unknown. This member doesn't match with any other member of the Horn/Horne DNA Project. 
 
Horn Group GG:  (1 member)  Christian Horne, born 1867 and died in 1944 in New Zealand. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group H:  (1 member)  Johan Mathias Horn, born 1718. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group HH:  (1 member)  Jesse Horne, born 1854 and died 1934. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group I:  (3 members)  Andreas (Andrew) Horn, born 1802 Rockensuss, Hessen, Germany. 
 
Horn Group II:  (2 members)  Hermann Horn, born 1848 in Kloster, Geringswalde, Germany. Also, John Horn, born 1784, ? Scotland.
 
Horn Group J:  (1 member)  Robert Horne, born 1723 in Marlborough, Massachusetts. This member doesn't match with any other member of the Horn/Horne DNA Project. 
 
Horn Group JJ:  (1 member)  Andrew Horn, born 1796 and died 1879. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group K:  (3 members)  Sherod Horn, born 1789 in White County, TN . The other ancestors are John Horn, born about 1730, and Stephen Horn, born 1833 in North Carolina.  
 
Horn Group KK:  (1 member)  Robert Henry William Horn(e), born 1799. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group L:  (1 member)  Johannes Horn. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group LL:  (1 member)  Unknown. This member doesn't match with any other member of the Horn/Horne DNA Project.

Horn Group M:  (1 member)  Jeremiah Horan, born about 1828, died 1870?. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group MM:  (1 member)  James Horne, born about 1792, died 1836. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group N:  (1 member)   Michael Harnar, born 1824,died 1892.  

Horn Group NN:  (2 members)  Tom Horn, born 1874 in Johnson County, KY. The other ancestor is John Horn, born c1725, Kirkintillich, Dunbarton, Scotland.

Horn Group O:  (1 member)  James Horn Esq., born 1725 in Baltimore County, MD, died 1792. This member doesn't match with any other member of the Horn/HorneDNA Project. 
 
Horn Group OO:  (1 member)  John Columbus Horn, born 1874, Mississippi. This member doesn't match with any other member of the Horn/Horne DNA Project.
 
Horn Group P:  (2 members)  Samuel Horn, born about 1835. 

Horn Group PP:  (1 member)  Jesse Horn, died 1795. This member doesn't match with any other member of the Horn/Horne DNA Project.

Horn Group Q:  (1 member)  Unknown. This member doesn't match with any other member of the Horn/Horne DNA Project.

Horn Group QQ:  (1 member)  Ludwig Horn, born c1786, died 1859. This member doesn't match with any other member of the Horn/Horne DNA Project.

Horn Group R:  (1 member)   Hans Jurgen Horn, born 1679, died 1742. This member doesn't match with any other member of the Horn/Horne DNA Project.

Horn Group RR:  (1 member)  Unknown. This member doesn't match with any other member of the Horn/Horne DNA Project.

Horn Group S:  (3 members)  Benjamin Horn(e) born 1765, died 1792, and Unknown