Philadelphia Magazine is moving its offices from a west Center City highrise into the historic Curtis building near Washington Square park.

The magazine's parent company, Metrocorp, signed a "long-term" lease for about 15,800 squre feet at the 601 Walnut St. office building, the Curtis's owner, Keystone Property Group, said in an email last week.

Philadelphia Magazine is leaving a space of a little more than 20,000 square feet at 1818 Market St., Keystone said.

The Curtis, built as the home to the Curtis Publishing Co. more than a century ago, is in the midst of renovations by Keystone that include the conversion of some space into apartments.