M25 Junction 16: the M40 at Denham
Junction 16 is where the M25 meets the M40, at Denham in Buckinghamshire. Two loops and long sweeping link roads carry traffic between the two motorways.
Live traffic speed flow: M25 Junctions 15 to 17
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Go to our live M25 traffic speed flow map ›
NOTE: The speed flow, overhead sign messages or other information shown on our live traffic speed flow map is updated every few minutes. We cross check the data and aim to provide warnings if there could be a delay or an inaccurate speed reading. There can be occasions, beyond our control, and despite our best efforts where the speed flow could be inaccurate. We cannot therefore guarantee the speed you can expect on any stretch of the motorway is always accurately shown. However we hope you will find our live traffic speed flow map a useful tool in trying to plan your journey. Safe driving.
Where the roads go
Take the M40 west for High Wycombe, Oxford and Birmingham, or east, where it becomes the A40 for Uxbridge and London. On the M25, the next junction anticlockwise is Junction 15 for the M4 and Heathrow, and clockwise it is Junction 17 at Maple Cross.
Between two of the busiest motorways
Junction 16 is the northern end of the M25 stretch from Junction 15, which the Department for Transport counted among the three busiest stretches of road in Great Britain in 2025. Traffic heading for Heathrow from the M40 joins the M25 here.
For news about the M40 itself, see our sister site M40 Traffic.
M25 Junction 16 at a glance
| Junction | M25 Junction 16 |
| Meets | the M40 (M40 Junction 1A) |
| Near | Denham, Uxbridge and Gerrards Cross |
| Next junction clockwise | J17 (A412, Maple Cross) |
| Next junction anticlockwise | J15 (M4, Heathrow) |
| Traffic news for the M40 | M40 Traffic |
Live traffic news at M25 Junction 16
Live traffic news at M25 Junction 16
Incidents and roadworks between Junction 15 and Junction 17 that we are aware of.
M25 Anti-clockwise Jct 16 to Jct 15 Lane 1,2 closure
01:02 (1:02am)14 Oct 2026reported 20 min ago
- Location
- M25 anti-clockwise within J15
- Direction
- Anticlockwise
- Lanes closed
- Lane closures
- Reason
- Roadworks
- Schedule
- 22:00 (10pm) Tue 13 Oct 2026 → 05:30 (5:30am) Wed 14 Oct 2026
+ 4 more near Junction 16 - see all the M25 traffic news →
This is the news for Junction 16 only, not the whole M25. For the rest of the motorway see all the latest M25 traffic news, the overhead signs and the speed limits in force now.
Updated 01:22 (1:22am) Wed 14 Oct 2026