Marcus & Millichap is pleased to exclusively present for sale the Decatur Professional Plaza, a five-story, 36,600 SF office building located at 363 S Main St in Downtown Decatur, Illinois (17th most populous city in Illinois). The property is situated at a prominent corner with frontage along Main St and Decatur St at a signalized intersection, the property covers 1.70 acres across two parcels and offers 100 onsite parking spaces, including 5 ADA-compliant spots. Built in 1967, masonry and steel construction, the building supports multi-tenant occupancy with flexible layouts. Recent CapEx improvements include a new roof (2019), chiller replacement (2024), and well-maintained HVAC system with 15 temperature control zones. Zoned B-2 for various commercial uses, the property features five floors of adaptable office configurations, ADA-compliant first-floor and third floor restrooms. The current tenant mix includes law offices, a travel agency, and salon services, establishing a stable service tenant base. Tenant amenities include terrazzo flooring, marble wall accents, wood wainscoting on upper floors, two passenger elevators, remodeled first and third floor restrooms and Parking lot LED lights. Located in Decatur’s Central Business District, the property is located near key institutions including the Macon County Courthouse, Decatur Civic Center, and various corporate offices. Decatur’s economy is anchored by major industries in agribusiness, manufacturing, and healthcare, including Fortune 500 companies, Archer Daniels Midland (ADM) and Caterpillar, as well as Primient and Ameren Illinois. Decatur Memorial Hospital and HSHS St. Mary’s Hospital further bolster the city’s healthcare sector. Major highways, including Route 36 and Business Route 51, ensure convenient connectivity. Decatur benefits from key infrastructure, including the Decatur Airport with nonstop service to Chicago, a labor force of approximately 533,000 within an hour’s drive, and efficient rail connections. The city’s population of 70,522 enjoys a favorable business environment, a low 18-minute average commute time, and access to over 4,700 acres of parks. The area is served by an educated workforce with nearby Millikin University (Enrollment 1800; ranked #1 regional college in Illinois by U.S. News & World Report) and Richland Community College (Enrollment: 2235). The universities align education with local industry needs to fuel workforce growth. The subject property has an occupancy of 55.31%, though has enjoyed much higher occupancy. In the summer of 2024, the air conditioning failed and was replaced by a new chiller.  Average building rent is currently $11.08SF ; average asking market rent is $20.17SF (1.4% annual rent growth) providing significant opportunity to mark rents to market in vacant suites.  Population (10 Mile):  95,343; Daytime Population (10 Mile) 102,971; Average Household Income (10Mile) $70,261.