Russia's TASS agency said 23 Kherson residents received a Russian passport at a ceremony through a "simplified procedure" facilitated by a decree signed by Russian President Vladimir Putin in May.
"All our Kherson residents want to obtain a passport and (Russian) citizenship as soon as possible," the regional administration's pro-Moscow chief Vladimir Saldo was quoted as saying by TASS.
"It's a new era that is beginning for us... It's the most important document a person can possess in their life," Saldo told the RIA Novosti agency.
The Kherson authorities said the timing of the passport distribution was chosen with Russia Day in mind.
It falls on Sunday and is a public holiday to mark Russia's independence from the former Soviet Union. It is an occasion for many Russians to display national pride.
The Russian army conquered most of the Kherson region at the start of its February 24 offensive.
The Kremlin decree authorising the local authorities to grant Russian passports to local residents also concerned the nearby Zaporizhzhia region partly controlled by Moscow's forces.
Ukraine denounced the move as a "flagrant violation" of its territorial integrity, saying Putin's decree was "legally void".