The Clan/Sept History

The name O Clery originally appeared in Gaelic as O Cleirigh, from the word
"cleireach," which means "clerk" or "cleric." The name denotes a descendant of
Cleireach, who was born around 820 AD, and descended from Guaire the Hospitable,
the famous king of Connacht.

One explanation for the many variations is that scribes and church officials
frequently spelled the name as it sounded: an imprecise method at best.
Understandably then, various spellings of the surname O Clery were found in the
many archives researched. These included Clery, Cleary, Claree, Clarey, Cleare,
Clearey, Clerey, O'Cleary, O'Clery, Macchlery, Clerkin, Clark and many more.
First found in county Donegal, and county Derry where they held a family seat
from ancient times.
Irish immigrants began to leave the English-controlled Ireland in sizable
numbers during the late 18th century. Many of these Irish immigrated to British
North America or the United States in the hopes of gaining their own tract of
farmland. This pattern of migration grew steadily until the 1840s when the Great
Potato Famine caused a great exodus of immigrants to North America. These
immigrants differed from their predecessors in that they were desperately
fleeing the disease and starvation that plagued their homeland, and many were
entirely destitute when they arrived in North America. Although these penniless
immigrants were not warmly welcomed when they arrived, they were critical to the
rapid development of the United States and what would become known as Canada.
Many went to populate the western frontiers and others provided the cheap labor
the new manufacturing sector and the building of bridges, roads, railways, and
canals required. A thorough examination of immigration and passenger lists has
revealed some of the earliest people to arrive in North America with name O
Clery or one of its variants: Thomas Clary, who arrived in the Virginia colony
in 1642; George Cleary, who was on record in Barbados plantation between the
years 1679 and 1680; Darby Cleary, who came to America in 1736.