The architect Joseph Crouwel jr., born 1885, designed the building in the style of the Amsterdamse School, inspired in part by the Finnish architect Eliel Saarinen. Construction ran from 1919 to 1924. The hall is the building's heart - parabolic arches sweep upward in a curve that recalls a railway terminal more than a civic office, the volume cathedral-scaled, the surfaces faced in glazed brick that softens the acoustics into something gentle. Yellow brick pigeons in relief flank the continent statues, symbolizing the telegraph service that once routed messages from this very hall. A large clock made by De Porceleyne Fles - the famous Delftware pottery - still hangs in the main hall. The building was given national monument status, a Rijksmonument.

Around 1400, a convent dedicated to Saint Cecilia stood on this site, home to nuns of the third order of Saint Francis of Assisi. The Protestant Reformation transferred the building to the municipality of Utrecht, and it continued in some form until 1647. Afterward, the Dutch National Mint moved in and operated here until 1911, when it relocated as the Royal Dutch Mint to Leidseweg 90. Inside the post office hall, a commemorative plaque - donated by the Utrechtsche Philatelistenvereeniging and designed by Maarten Pauw - recalls the National Mint's tenure and a particular date: 27 December 1851, when the first Dutch postage stamp was issued here. The Mint building was demolished in 1919 to make way for Crouwel's design. Each tenant has left a layer.

On 28 October 2011, Utrecht Post closed. It was the very last independent post office in the Netherlands, a fact that reads almost as a kind of national obituary. The internet had arrived. Email had replaced letters. The Dutch postal service consolidated into supermarket counters and retail kiosks, and the great civic post offices of the early twentieth century - including this one - went dark. For several years the Crouwel building sat empty. Owners changed: KPN, the Dutch telecom company that had long shared the upper floors, sold its interest in 2008 to Fortis Vastgoed, now ASR Nederland real estate development. Conversion began in 2016. The challenge was finding a new public purpose worthy of the parabolic hall.

For most of the twentieth century, PTT Telecom, forerunner of KPN, occupied the upper floors. Within PTT's network the building was known as UT1. By the 1990s an Ericsson AXE traffic center called UT1F handled much of the telephone traffic of the province of Utrecht and the Betuwe. A 5ESS exchange called UT1D served Culemborg, Tiel, and Woerden. Another, UT-C1G, handled parts of Utrecht city and surrounding towns including Maarssen and Breukelen. Beneath the building, the cellar held the bundles of telephone cables that connected the city. The continent statues in the hall above watched it all in silence. The combination - post office below, telephone exchange above, telegraph pigeons in brick relief, mint history on a plaque, a Saint Cecilia convent in the foundations - made the building one of the most layered civic spaces in the country.

Since 2020, the Hoofdpostkantoor has served as the headquarters of the Utrecht Public Library. The new branch was originally scheduled to open on 13 March 2020, but the COVID-19 pandemic intervened, and public access only began in phases starting on 11 May. The library reading rooms now spread across the spaces where postal clerks once worked. Broese Booksellers opened a new shop in the rear of the building along the Oudegracht canal on 23 April 2020, with Utrecht novelist Ronald Giphart cutting the ribbon. At the entrance hangs a neon work by Maarten Baas titled 'Intellectual Heritage,' a phrase that reads as either earnest or wry depending on the mood of the day. Visitors who never knew the post office still feel the building's weight - the parabolic arches, the continent statues, the De Porceleyne Fles clock - and the building, for the first time in its hundred-year life, exists to gather words rather than send them.