It shares borders with the cities of Ansonia to the north and Shelton to the southwest, and the towns of Orange to the south, Seymour to the northwest, and Woodbridge to the east.

[7][8] Derby was settled in 1642 as an Indian trading post under the name Paugasset by John Wakeman of New Haven, though fur traders had been in the area before and Native Americans had lived there for centuries.

[25] Saint Michael's the Archangel Parish, a Roman Catholic church, serves mass in Polish as well as English.

[31][32] In 2017, Moody's Investors Service downgraded the city's bond rating from AA to AA−, citing "weak budgetary performance" in 2016.

[33] Grand list[34] 2016 – $1,028,072,826.82 2010 – $1,091,576,401.00 Mill rate[35] Notable businesses Factory Street Square In 2018, a development group working with the owners of the Baretta Landscaping property submitted a conceptual design to the planning and zoning commission for a four-phase 400-unit high density residential and commercial development on Factory Street in downtown Derby.

The project, called Factory Street Square, was to be built in four phases over the next four to six years on unused light industrial property.

The proposed buildings would sit on five acres of near-vacant land, and would be four stories high with first floor retail shops and restaurants, with residential space above.

The project, tailored toward attracting Millennials and empty nesters to the area, will offer amenities not seen in other residential complexes in the city, including a health club; indoor golf simulator; rooftop garden; dog-sitting, walking, and grooming service; and an in-complex library.

The site is located one block from rail and bus lines that meet at the Derby-Shelton Railroad Station, making the project a transit-oriented development.

Multiple development projects have been proposed, from high density mixed use to big-box retail plazas, but none have been successful.

In 2019, the last four buildings on the south side of Main Street were demolished; following delays, the widening project had a tentative construction start date of early 2020.

[61] In 2017, Derby had one homicide, two rapes, 16 robberies, 23 aggravated assaults, 35 burglaries, 238 larcenies, 33 motor vehicle thefts, and two arsons.

[74] The Derby section of the Naugatuck River Greenway System is the busiest multipurpose trail in Connecticut, with 302,550 trips counted in 2017.

The park includes the Osbornedale Homestead, the Kellogg Environmental Center,[76] Pickett's Pond,[77] and an extensive system of hiking trails.

The park offers field sports, hiking, ice skating, museum tours, picnicking, pond fishing, and rental of pavilions for outings.

The property, formerly a reservoir, dates back to 1859 when the burgeoning Borough of Birmingham (present-day Downtown Derby)[79] needed a stable water supply.

Civil War Monument In 1875, the Elisha S. Kellogg Post of the Grand Party of the Republic raised $1,475 to erect a statue to honor the soldiers of Derby and Huntington (now Shelton) who served in the Union forces.

On November 16, 2001, 94 year-old Ottilie Lundgren of Oxford was brought to Griffin Hospital in Derby, experiencing difficulty breathing and cold-like symptoms.

The test was confirmed and treatment began, but was unsuccessful, and Lundgren died on November 22, 2001, making her the fifth and final victim of the 2001 anthrax attacks.

Lundgren's home in Oxford was quarantined and searched by the FBI and Connecticut State Police, but nothing was found that indicated how she had been exposed.

However, Irvins took his own life shortly after the FBI named him as the primary suspect, and no formal charges or direct evidence has been found to substantiate these accusations.

On December 6, 1985, at approximately 3:45pm EST, a three-story brick building, located at 268 Main Street in Derby, collapsed following a natural gas explosion, killing six people and injuring dozens.

The River Restaurant located on the main level of the building had 18 customers and employees inside when the explosion occurred.

Residents and businesses within a ten-block radius were evacuated as a precaution while firefighters worked to find those trapped in the debris.

[90][91]On August 12, 1991, at approximately 6:56pm EST, a fire broke out in the basement of a three-story, six-family home located at 269 Caroline Street.

The fire department rapidly struck a second and third alarm for additional resources from the surrounding area, including Ansonia, Shelton, Seymour, and Orange.

[94] The crest of the Naugatuck River reached 25.70 ft above flood stage, the highest in recorded history, which it still maintains to this day.

[95] Low-lying cities in the area, such as Derby, Shelton, Ansonia, Seymour, Beacon Falls, and Oxford all suffered impacts from the flood.

The development group built seven homes on the remaining six acres, and the historic Singer mansion sits at the end of the newly constructed dead-end street.

The company remains unique in the publishing industry in that every phase of production (editorial, printing, and distribution) took place under one roof.