Possible Clues:

• It has banks in St. Petersburg
• Lake Tahoe's aptly named Cal __ Casino
• St. Petersburg's river (anagram of VANE)
• River through St. Petersburg
• River that passes by the Hermitage
• River flowing past the Hermitage Museum complex
• This one is in Russia
• It flows past the Hermitage Museum
• Cal ___ Resort & Casino (Lake Tahoe property once co-owned by Frank Sinatra)
• Russian river to the Gulf of Finland