The list, announced on the department's Web site, included Sajjid Mir, accused of coordinating the three-day November 2008 attacks in Mumbai in neighboring India in which 166 people died.
The LeT has already been designated as a foreign terrorist group both by the U.S. State Department and the United Nations.
The Treasury action means U.S. nationals are barred from engaging in any transaction with those on the list, whose assets under U.S. jurisdiction would be frozen.
The Long War Journal reported Mir has been identified in another study as a former Pakistani military officer.
"Today's action against LeT is Treasury's most comprehensive to date against this group and includes individuals participating in all aspects of LeT's operations -- from commanders planning attacks to those managing LeT's relationships with other terrorist groups," David S. Cohen, Treasury's undersecretary for terrorism and financial intelligence, said in a statement.
The Treasury Department said the LeT has conducted numerous terrorist acts against Pakistani, Indian, Afghan and U.S. interests and is responsible for the November 2008 Mumbai attacks.
The Long War Journal report said Mir even had eyes on the United States, where he recruited four operatives for monitoring target sites.
Another person on the list is Talha Saeed. The Journal said he is the son of LeT founder Hafiz Saeed, who reportedly had been close to al-Qaida leader Osama bin Laden prior to the latter's death in May 2011.
India has said Hafiz Saeed is one of the leaders who masterminded the Mumbai attacks.
Pakistan's Express Tribune said the others on the Treasury list include those accused of attacks on coalition and Afghan forces in Afghanistan.