When was the US 5000 dollar bill last in circulation?

Technically, large-denomination notes are still legal tender because the US has never withdrawn any Federal Reserve Notes, US Notes, or silver certificates.

Bills larger than $100 were never common in circulation because of their high value, especially in the days before inflation was a way of life. For example a $5000 bill could buy a house in the 1930s. The last series year was 1934 although printing actually continued until 1945.

After WW2 new forms of non-cash payment were becoming more common, so no more large bills were needed for over 2 decades. In the 1960s electronic payment systems started to be developed, further reducing demand in legitimate commerce. However banks were still allowed to supply large bills, and the spread of illegal drugs and weapons made them attractive to criminals as a way of hiding big transactions. To make it harder to launder illegal activities, in July 1969 the government ordered banks to stop distributing any bills larger than $100 and to return any that were brought in for deposit or exchange. With those actions the use of high-denomination bills in legitimate commerce trailed off to essentially zero.

Due to inflation, there have been proposals to bring back the $500 bill or issue a new $200 bill similar to the €200 bill in Europe. But today the widespread use of electronic cash means it's extremely unlikely either denomination will be printed.
Circulation of all high-denomination US Dollar bills was halted in 1969.