Two Scots - Kim Little and Ifeoma Dieke - are the only non-English among the 18 selected for the Games, with Wales and Northern Ireland not represented.
Powell, England's manager since 1998, said: "I didn't feel any pressure to include players from Northern Ireland or Wales. I was tasked with picking the best squad of players and that's what I've done. We had everyone looked at extensively."
She added: "I took the associations out of the equation and it was just about trying to pick a squad of players that I felt would do the best job possible. The location of the first game being in Cardiff did not nag my mind at all when it came to selecting a Welsh player.
"There's no disrespect to anyone, but my task was to pick the best players and I think I've done that. It was quite a challenging task and that goes to show the amount of talent we have to choose from. Since we knew there'd be a Team GB we spoke to other associations and managers and we had all teams looked at.
Arsenal Ladies playmaker Kelly Smith features in the squad after winning her latest injury battle, having sustained a broken leg in March. Smith, who has scored 45 goals in 111 caps, has been England's most creative player since beginning her international career in 1995 and Powell was delighted by her fitness.
"Kelly's doing really well. There have been question marks because she's been injured," Powell said. "But she's been in intensive rehab and she came on at the weekend. I've spoken to her and our medics. She's absolutely champing at the bit and is good to go. We all know the sort of player she is and is looking good."
The eyes of the sporting world will be watching when Team GB open the tournament against New Zealand at the Millennium Stadium on July 25. It will be the first competitive action of the Games and Powell admits it offers a unique opportunity to catapult the women's game into the public consciousness.
"When we get the squad together we'll make everyone aware of the expectations and the media attention around that opening game," she said. "Hopefully everyone will settle into the groove of the Olympics and the main thing is to enjoy it and what it will bring women's football.
"London 2012 gives us a great platform to raise the profile of the women's game."