Powys has a total of 73 seats
The Conservatives have made huge gains in the local elections in Powys, going from having no councillors to winning nine seats.
Six of the wards are in the old county of Montgomeryshire, with three traditional Welsh-speaking communities falling into Conservative hands.
Tory parliamentary candidate Glyn Davies said it had been his "most successful night" in politics.
In Ceredigion, Plaid is the largest group, but is not in overall control.
The party fell short of the 22 seats needed to rule the council, but it made three gains despite losing long-serving councillor Penri James.
Mr James, who is also Ceredigion's prospective parliamentary candidate, was one of the leading casualties.
Among the main casualties in Powys was the leader of the Welsh Liberal Democrat group James Gibson-Watt, who lost his seat in Hay-on-Wye to the Conservatives.
The Tories also gained the wards of Llandrindod Wells north and south, Newtown central, north and west and the traditionally Welsh-speaking areas of Llanfyllin, Llanwddyn and Llanrhaeadr-ym-Mochnant.
Conservative prospective parliamentary candidate in Montgomeryshire, Glyn Davies, said 24 hours ago his party was not represented on Powys Council.
"This is the most successful night I've ever had in politics," said Mr Davies, who is a former AM.
"The result means the Conservatives qualify for two seats on the council's ruling board."
Tory leader in the assembly, Nick Bourne, said: "This is superb news and a testament to all the hard work of our Powys team."
Before the election, 53 councillors in two different groups were recognised as independent, but that number has fallen to 38.
The Liberal Democrat total has remained unchanged with 15 seats, as has Labour with four. A further seven councillors are not members of political groups.
Powys Council said the political make-up of the authority would not be known until after its annual meeting later this month.
In Ceredigion, one of the major casualties was the former Plaid group leader on the council, Penri James.
He lost his Tir Mynach seat by 12 votes to Lib Dem Paul Hinge. Mr James left the count without commenting. But with all results declared Plaid has won 19 seats, the Independents have 12 seats, the Lib Dems 10 and Labour one.
The previous administration was run by an Independent Group and Liberal Democrat coalition, with Plaid in opposition.
WHO RAN COUNCILS IN MID WALES FROM 2004 - 2008
Ceredigion: Independent / Liberal Democrat / Labour
Keith Evans, the leader of the independent group and the leader of the council held his Llandysul seat, and Elen ap Gwynn, the leader of Plaid Cymru group, retained Ceulan and Maesmawr.
Among the other main casualties in the county was the Independent Group's Emlyn Thomas, a member of the cabinet, who lost his seat in Aberaeron to Lib Dem Elizabeth Evans.
Mair Morris, a fellow independent and cabinet member, also lost her seat.
However, the independents did gain the Llansantffraid ward from Plaid Cymru.
Council leader Keith Evans said it had been a "topsy turvy night", but the group would discuss its options.
The Liberal Democrats increased their wards from nine to 10 and will also discuss their options, said council group leader Ceredig Davies.
Ceredigion Lib Dem MP Mark Williams said: "We are delighted with tonight's results.
"Our votes in the wards have gone up massively. We've gained two seats and Plaid Cymru has lost a seat to the independents and to us."
Turnout was reported to be high, up to 70% in some areas in the south of the county such as Cardigan.
Plaid's group leader on the council, Elen ap Gwynn, said overall it had been a successful night and the party would speak to other groups about forming a coalition.