Where was, and what was the diameter of the largest tornado ever recorded?

The Hallam, Nebraska F4 tornado of 22 May 2004 is the newest record-holder for peak width, at nearly two and a half miles, as surveyed by Brian Smith of NWS Omaha. This is probably close to the maximum size for tornadoes; but it is possible that larger, unrecorded ones have occurred.
http://www.spc.noaa.gov/faq/tornado/

The widest tornado (defined as damage path, not condensation/debris cloud or radar measurements) on record is the Wilber - Hallam, Nebraska tornado during the outbreak of May 22, 2004, with a width of 2.5 miles (4 km) at its peak.

The widest tornado as measured by actual radar wind measurements was the Mulhall (1999) tornado in northern Oklahoma which occurred during the 1999 Oklahoma tornado outbreak. The distance between the maximum winds on each side of the tornado (over 110 m/s) was over 1600 m

https://en.wikipedia.org/wiki/Tornado_records#Widest_damage_width

2013 UPDATE

On May 31, 2013 an EF5 with one main and many satellite vortexes ran through El Reno, Oklahoma. The main funnel was measured by radar to be 2.6 miles wide. The toroidal debris ring surrounding the base of the main funnel was measured to be 3 miles wide. There were at least 14 deaths associated with it, though many seem to have been drownings from poorly sheltered victims caught in flash flooding and not directly from the wind event. Three storm chasers were killed in their vehicle when it was caught by winds estimated at around 300 mph in a satellite vortex. Another vehicle, this one from "The Weather Channel" was caught by one of the vortexes and tossed 200 yards sending the three occupants to the hospital for various injuries. Their car was flattened like a pancake.

https://en.wikipedia.org/wiki/May_26%E2%80%9331,_2013_tornado_outbreak

The widest tornado ever recorded occurred between Wilber and Hallam, Nebraska. The tornado was 2.5 miles wide.

http://wiki.answers.com/Q/What_was_the_widest_tornado_ever_recorded

The longest track single tornado is the Tri-State Tornado, which traversed greater than 219 miles (352 km) across southeastern Missouri, southern Illinois, and southwestern Indiana in about 3.5 hours. Though there has been some discussion as to whether this was a single tornado or a tornado family, recent and ongoing detailed reanalysis has found no break in the path and in fact that the tornado began 15 miles (24 km) before previously thought.

https://en.wikipedia.org/wiki/Tornado_records

Is longest lived the same as largest or is widest? (And then width is also not meant to mean highest on the EF scale) Copied from wiki for tornado with widest damage path:
"The widest tornado (defined as damage path, not condensation/debris cloud or radar measurements) on record is the Wilber - Hallam, Nebraska tornado during the outbreak of May 22, 2004, with a width of 2.5 miles (4.0 km) at its peak. It was an F4."

https://en.wikipedia.org/wiki/Tornado_records#Largest_and_most_powerful_tornadoes