Laura Diaz posted a 3-under-par 68. She was joined in a tie for third place by Leta Lindley, Kristen Samp, Cristie Kerr and Jill McGill.
Annika Sorenstam, who is trying to win her sixth straight start which would set an LPGA Tour record for consecutive wins, opened with a 5-over-par 76. For Sorenstam, the 76 snapped a streak of 43 straight rounds of par or better.
Sorenstam picked up a birdie and a bogey over her the first seven holes as she started on the 10th tee. She struggled to four bogeys over her next six holes. Sorenstam fell to plus-6 with a double bogey at the seventh. She recovered one stroke with a birdie on the ninth, her last.
'I thought I played good today,' said Sorenstam. 'It just didn't go my way at all. It was just one of those days. It was not the start I had in mind.'
Cavalleri faltered to a bogey at the first after her second shot found a greenside bunker. She bounced back with an eagle from 20 feet out at the par-5 seventh. The Italian moved to 2 under with a 10-foot birdie putt on the eighth of the River Course at Kingsmill Golf Club.
The 32-year-old Cavalleri parred her next two holes around the turn. She dropped in another 10-foot birdie putt at the par-4 11th. Cavalleri carded her final birdie at the par-5 15th before parring her final three holes.
'It is always tough to play in the wind, especially on this course,' Cavalleri said. 'There were some holes between trees where the wind was swirling. Plus, the greens were hard. There is not a lot of room where you can hit the green and stay on the green.'
Nilsmark got her round going with a birdie at the opening hole. She parred five straight holes before collecting her second birdie at the seventh after she chipped to five feet.
The Swede moved to minus-3 with a 12-foot birdie putt on No. 9. Nilsmark moved to 4 under with a 9-foot birdie putt at the par-4 11th.
Nilsmark did stumble to a bogey on No. 13. The 2003 European Solheim Cup captain recovered that lost stroke with a 25-foot birdie putt on the 15th. Nilsmark parred her final three holes to share the lead.
'Today I hit the ball really well. I have just been back from Sweden for four weeks,' said Nilsmark. 'I am rusty around the greens and on the greens. I took a new putter this week. I looked at it after the putt on No. 1, it didn't feel wonderful. The grip was all crooked, but I managed to hang in there.'
Shi Hyun Ahn, Grace Park, Jan Stephenson, Mi Hyun Kim and Natalie Gulbis are among 16 players tied for eighth place at 2-under-par 69.
Defending champion Se Ri Pak got off to a rough start as she shot an 8-over-par 79.