Before the Earl Carlo Borromeo bought this island it was a barren piece of land. In 1630 gave the Earl assignment to the Milanese architect Giovanni Angelo Crivelli to build the palace with garden, in the place which at that time was no more than a bare rock inhabited by fishermen. The island was named after his wife "Isabella" D'Adda, later the name would be shortened to "Bella". Isola Bella was an island with terraced gardens, grottos, fountains, statues and white peacocks. Together with the Palazzo Borromeo everything was designed in the Baroque style of the sixteenth century.

The luxuriously furnished rooms have been preserved with furniture and a beautiful collection of precious Flemish tapestries. The palace is a series of rooms with furniture of the past centuries, compiled by Mussolini and Napoleon.

On the first floor is the large ballroom used for the reception and representation. Then we find the Hall of Columns in neoclassical style, the Board of Directors of the music takes its name from the exhibit valuable musical instruments and the Board of Directors of the medals, which retains medals gilded wood represent the most important event in the life of St. Charles Borromeo. On this floor we find a Gallery of Tapestries.

A collection of valuable Flemish tapestries designed and made during the sixteenth century. The vaulted ceiling of this room is decorated with pink windows of gold on a white background. Very special and valuable are the artificial caves, which are accessible via a spiral staircase from the eighteenth century, marked with marine motifs.