The "wanted" notice announcing the large bounty for Saeed, 62, was posted on the website of the U.S. State Department's Rewards for Justice program late Monday.
The program was established in 1984 and has paid some $100 million to more than 70 people for information about terrorists. Rewards go as high as $25 million for information on al Qaeda leader Ayman al-Zawahiri.
The State Department calls the program "one of the most valuable assets the U.S. government has in the fight against international terrorism."
The amount for Saeed is one of the highest offered by the program, on par with the sum pinned on Taliban leader Mullah Omar.
The notice describes Saeed as a former professor of Arabic and engineering who helped found Jamaat-ud-Dawa, a radical Muslim organization that aims to bring about Islamist rule in India and Pakistan.
The group's military wing, Lashkar-e-Tayyiba, which means army of the pure, is blamed for violence in the disputed territory of Kashmir aimed at liberating Muslims.
After the September 11, 2001, attacks in the United States, Lashkar-e-Tayyiba began operating outside Kashmir. It is suspected of carrying out several high-profile attacks in India in the past few years.
The United States labeled it a "foreign terrorist organization" in December 2001, and under pressure from Washington, Pakistan banned the group in 2002. But the group continues to function quite freely.
In November 2008, terrorists stormed locations throughout Mumbai, killing scores of people and taking hostages. Six American citizens were killed in the carnage.
In a rare interview in 2010, Saeed told The Independent newspaper that Lashkar-e-Tayyiba was not involved in the attacks, despite substantial evidence to the contrary.
The Indian government has issued a notice with Interpol against Saeed in relation to his alleged role in the Mumbai attacks.
On Tuesday, India welcomed the reward notice.
"It reflects the commitment of India and the United States to bring the perpetrators of the Mumbai terrorist attack to justice and continuing efforts to combat terrorism," the Ministry of External Affairs said in a statement.
"It also sends a strong signal to [Lashkar-e-Tayyiba] and also its members and patrons that the international community remains united in combating terrorism."
Muhammad Yahya Mujahid, the spokesman for Jamaat-ud-Dawa, said the bounty was yet another attack on Islam and Muslims.
"The only thing these American actions will do is create a more passionate hate for America in the hearts of Muslims," he said.
Saeed, the spokesman said, has not been "hiding in mountains and caves" but living openly in Pakistan.
He is scheduled to address a rally Tuesday in Abbotabad, Mujahid said.
