William Harrison (Pneumonia) Zachary Taylor (Acute Gastrointestinitis) Abraham Lincoln (Assasinated) James Garfield (Assasinated) William McKinley (Assasinated) Warren Harding (Heart Attack) Franklin Roosevelt (Cerebral Hemorrhage) John Kennedy (Assasinated)
James Buchanan was President from March 4, 1857 to March 4, 1861. Abraham Lincoln was elected in 1860, took office in 1861, and was reelected in 1864. He was assasinated just a month into his second term, in April 1865.
No United States president has been removed from office, excluding those that were assasinated while in office. There were impeachments, but they did not lead to removals from office (Nixon resigned before it might have happened).
In 1897, President William McKinley was elected with Thoedore Roosevelt as his vice president. However, in 1901, William McKinley was assasinated by Leon Czolgosz, and Theodore Roosevelt became president.
No, he was the first president of the US. Abraham Lincoln was the 16th But, He was however the 16th President of the Continental Congress. The first president of the Continental Congress was Peyton Randolph and some people do consider him the "first" President.