She will take over from Liberal Democrat councillor Trevor Chapman who has held the role since April 2021 during a term disrupted by the coronavirus pandemic.
Speaking at a full council meeting last night, councillor Oldham said it was an "absolute thrill" to be nominated.
Conservative council leader Richard Cooper congratulated councillor Oldham on her nomination, saying: "Vicky and I have known one another since she first became the candidate for the Washburn ward.
"It was my great pleasure to support her during that by-election, and it will be my great pleasure to support her during her mayoral year."
Councillor Pat Marsh, leader of the opposition Liberal Democrat group, also described the nomination as "wonderful".
She said: "Not only will Vicky be our last civic mayor, but she is female and she is rural. Those two pluses are amazing."
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Councillor Oldham will be the final ever mayor on Harrogate Borough Council as the authority will be abolished and replaced with a new North Yorkshire Council from April 2023.
Elections to the new council will take place this May.
The role of the mayor is to chair full council meetings and represent the borough at ceremonies and events. They also raise money for charities and are required to put their political affiliations aside to be impartial.
Also at last night's meeting, Conservative councillor Robert Windass, who represents the Boroughbridge ward, was also elected as deputy mayor.
He will take over from Liberal Democrat councillor Christine Willoughby who represents the Knaresborough Eastfield ward.
The new mayor and deputy mayor will be officially sworn in at an annual full council meeting in May.
By Jacob Webster, Local Democracy Reporter