The official beginnng and ending dates for past recessions are shown at the link to the National Bureau of Economic Research's site. Wondering what a recession is? According to the NBER, the official arbiter of when recessions begin and end,
"A recession is a significant decline in economic activity spread across the economy, lasting more than a few months, normally visible in production, employment, real income, and other indicators. A recession begins when the economy reaches a peak of activity and ends when the economy reaches its trough. Between trough and peak, the economy is in an expansion."
