What is the name of the first Power Rangers series to air in the 2000s?

The first Power Rangers series to air in the 2000s was Power Rangers: Lightspeed Rescue.

Lightspeed Rescue premiered on February 12, 2000, making it the franchise’s first season to begin in that decade. It followed Power Rangers Lost Galaxy, which aired from 1999 into 2000, so the distinction depends on a series’ premiere date rather than on whether any episodes happened to air during the decade.

The story moves the action to fictional Mariner Bay, California, where the government-backed Lightspeed organization recruits five civilians to defend the city from demons. The team includes a firefighter, lifeguard, stunt pilot, extreme-sports athlete, and paramedic, giving the season a rescue-services theme.

Lightspeed Rescue also introduced the Titanium Ranger, the first American-exclusive Ranger without a direct counterpart in the Japanese Super Sentai footage used as the series’ source material. The later series Time Force, Wild Force, and Ninja Storm all premiered after it, in 2001, 2002, and 2003 respectively.