Officers were said to be "in absolute shock" about the gathering in Dover Street, Normanton, at 10pm on Saturday, which defied new Government lockdown rules put in place to stop the spread of coronavirus.
Derbyshire Police posted photos of the party on social media, showing a table covered in food and drink and large speakers in use.
The force told the PA news agency that "strong words of advice" were given to all those inside and the party was dispersed but no further action was taken.
A Twitter account for Derbyshire Police, @DerWestResponse, tweeted: "Officers have just attended an address in absolute shock to find 25 adults and children having a massive party with speakers and karaoke.
"It is clear people are still having complete disregard for the Government advice and rules."
This week, Derbyshire Police introduced measures to prevent gatherings in the county by dyeing a "blue lagoon" in Buxton black to deter visitors.
The force had already come under fire from some quarters for using drone footage to shame people travelling into the Peak District to walk in the hills.