In the original description of his newly introduced Ypresian stage Dumont (1850) did mention neither stratotype nor type locality.

[2] Since 2003, the Global Stratotype Section and Point (GSSP) defined by the International Commission on Stratigraphy (ICS) for the Ypresian is set in the Dababiya section close to Luxor, Egypt,[3] where the uppermost Tarawan Limestone, the Esna Formation and the lowermost Thebes Limestone define the Ypresian sequence.

[4] Several other proposals for the lithostratigraphic redefinition of the top of the Ypresian exist;[5] among others the Punta Torcida Formation of the Austral or Magallanes Basin in Tierra del Fuego, the Azkorri Sandstone in the Gorrondatxe section of the North Pyrenean Foreland or Basque–Cantabrian Basin,[6][7] the Agost section close to Alicante in the Agost Basin in the Betic Cordillera,[8] and the Fortuna section north of Murcia in the Prebetic realm of the Betic Cordillera,[9][10] all in Spain.

Other proposed type sections for the Ypresian-Lutetian boundary are located in France, Italy, Israel, Tunisia, Morocco, Cuba and Mexico.

It occurs in the west and north of Belgium, the Tielt Formation, consisting of fine sand, is found in the subsurface of western and central Belgium and the Gentbrugge Formation, which comprises an alternation of clay, silt and fine sand, crops out in East and West Flanders.