European route E231
European routes in the Netherlands with E 231 in dark green
|Maintained by Rijkswaterstaat|
|International E-road network|
- E 35 / A10 in Amsterdam
- A9 in Diemen
- A6 in Muiderberg
- A27 near Hilversum
- E 30 / E 232 / A1 / A28 in Amersfoort
The route that E 231 follows was originally called E 35 in 1950 in the Declaration on the Construction of Main International Traffic Arteries. That route started in Amsterdam, passed by Amersfoort, E 231's current eastern terminus, Groningen and Bremen, and ended in Hamburg. In the 1950 version of that declaration, there were no routes numbered E 230 and E 231 yet. In 1975, E 230, a new route in the system, was defined and proposed as a road between Amsterdam and Amersfoort, the same route as it follows today. The 1975 version of E 231 followed today's E 232's route from Amersfoort to Groningen. E 35 was also laid down on a new course, running from Hoek van Holland, passing by Rotterdam, Utrecht, Oberhausen, Cologne, and Basel, to Rome. These plans were put into force on 15 March 1983. In 1987, E 230, defined in 1975, was renumbered to E 231. E 231 was renumbered to E 232. E 35 was also rerouted again, now starting in Amsterdam, but following the same route once arrived in Utrecht. 
In 1950, when E 35 was proposed, much of the underlying road wasn't constructed yet. The first part of the motorway to be completed was the Merwedebrug in 1933, now replaced with the Muiderbrug, with only one lane in each direction. Before 1942, construction started on embankments from Baarn to Amersfoort, but construction was discontinued due to World War II. In 1948 planning was continued and in 1952 Rijksweg 1, now also known as A1, was opened between Baarn and E 231's current eastern terminus Hoevelaken, which was merely a roundabout back then, compared to the cloverleaf interchange that is located there now. That part of the road had one lane in each direction and at grade intersections, but was already upgraded to have grade separated intersections in 1953.
|North Holland||Amsterdam||4.5||2.8||—||Watergraafsmeer Interchange||E 35 / A10 – Amsterdam, Rotterdam, Purmerend, Zaanstad||West end of A1 overlap|
|Diemen||5.6||3.5||1||Diemen-Noord||Landlust / Diemerpolderweg / Vlinderweg||Westbound entrance and eastbound exit only|
|6.8||4.2||2||Diemen||S114 (Weteringweg) / Diemerpolderweg – Diemen, Amsterdam-IJburg|
|8.0||5.0||—||Diemen Interchange||A9 south – Haarlem, Schiphol, Amsterdam-Zuidoost, Utrecht|
|15.6||9.7||—||Muiderberg Interchange||A6 north – Lelystad, Almere|
|17.0||10.6||5||Naarden-West||Rijksweg / Churchillstraat||Westbound entrance and eastbound exit only|
|Huizen||24.7||15.3||8||Blaricum||N527 north (Crailoseweg) to N526 east (Prins Hendriklaan) / Amersfoortsestraatweg / Rijksstraatweg – Blaricum, Huizen|
|Laren, North Holland||27.0||16.8||9||Hilversum-Noord||N525 south (Hilversumseweg) / Hilversumseweg – Hilversum|
|28.6||17.8||9a||De Witte Bergen||Rijksweg / Heidelaan|
|Utrecht||Eemnes||29.6||18.4||—||Eemnes Interchange||A27 – Hilversum, Utrecht, Almere|
|31.0||19.3||10||Soest, Netherlands||N221 south / Zandheuvelweg / Wakkerendijk – Soest, Netherlands, Baarn|
|Baarn||34.1||21.2||11||Eembrugge||N414 (Bisschopsweg) – Eembrugge, Baarn|
|Amersfoort||39.0||24.2||12||Bunschoten-Spakenburg||N199 (Bunschoterstraat / Amersfoortsweg) – Bunschoten-Spakenburg, Amersfoort|
|42.0||26.1||13||Amersfoort-Noord||Bergpas / Rondweg Oost|
|44.6||27.7||—||Hoevelaken Interchange||E 30 / E 232 north / A1 east / A28 – Utrecht, Zwolle, Apeldoorn, Arnhem||East end of A1 overlap|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- "Wegbeheerders". Rijkswaterstaat. Retrieved 12 January 2017.
- "Declaration on the construction of main international traffic arteries". 16 September 1950. Retrieved 31 January 2017.
- "European Agreement on main international traffic arteries" (PDF) (in English, French, and Russian). United Nations Economic Commission for Europe. 15 November 1975. Retrieved 31 January 2017.
- "Tractatenblad van het Koninkrijk der Nederlanden - Jaargang 1987 Nr. 13" [Treaty Series of the Kingdom of the Netherlands - Volume 1987 No. 13] (in Dutch and English). Overheid.nl. 19 January 1987. Retrieved 31 January 2017.
- "Dossier A1" [Dossier A1] (in Dutch). Autosnelwegen.nl. 6 August 2016. Retrieved 1 February 2017.
- "Stichting Incident Management Nederland". Retrieved 18 January 2017.
- Media related to European route E231 at Wikimedia Commons