Quick fix: Open Settings → System → Display and click Identify — a large number appears on each connected monitor showing which one Windows calls 1, 2, 3, etc.

You have two or three monitors connected and need to know which one is “Display 1” in Windows settings, “Display 2,” etc. Maybe you want to set different wallpapers per monitor, rearrange their layout, or designate the primary display. Windows has a one-click identification feature, plus PowerShell commands for scripted identification.

Symptom: Need to identify which physical monitor corresponds to Windows’ Display 1, 2, 3 in Settings.
Affects: Windows 11 (and Windows 10) multi-monitor setups.
Fix time: ~2 minutes.

What causes this

Windows assigns each connected monitor a number based on the order it was detected by the graphics driver during boot — not based on physical position. The same hardware setup can swap numbers between reboots if cables are reconnected, monitors are powered on/off in different orders, or graphics drivers update. The Identify button shows the assignment so you can confirm or adjust.

Method 1: Use the Identify button in Settings

The simplest and most visual approach.

Open Settings → System → Display.
At the top of the page, you see a graphical layout with rectangles representing each monitor (labeled 1, 2, 3, etc.).
Click the Identify button below the layout.
A large number appears in the lower-left of each connected monitor for a few seconds. The number matches the label in Settings.
Now you know which physical screen is which number. To rearrange: click and drag the rectangles in Settings to match your physical arrangement (e.g., put 2 on the right of 1 if monitor 2 is physically right).
Click Apply to save the arrangement.
To change which monitor is primary: click the rectangle of your chosen primary, scroll down, tick Make this my main display.

This handles the visual identification and lets you rearrange layout to match physical reality.

Method 2: PowerShell for scripted identification

Use when scripting display configuration or in scenarios where the Settings UI isn’t convenient.

Open Terminal (Admin).
List all monitors with details:
```
Get-PnpDevice -Class Monitor | Where-Object Status -eq "OK" | Format-Table FriendlyName, InstanceId
```
The FriendlyName usually contains the monitor model (e.g., Dell U2723QE, LG ULTRAFINE).
Get current display configuration via Win32 API:
```
Add-Type -AssemblyName System.Windows.Forms
[System.Windows.Forms.Screen]::AllScreens | Format-Table DeviceName, Bounds, Primary
```
DeviceName shows internal IDs (\\.\DISPLAY1, etc.); Bounds shows coordinates; Primary indicates which is the main display.
To set the primary display via PowerShell, third-party tools like nircmd work:
```
nircmd.exe setprimarydisplay 2
```

This approach is useful for setup scripts or remote configuration where opening Settings isn’t practical.

Method 3: Use the monitor’s OSD or built-in tools to verify

For cross-verification when the Identify button doesn’t work (rare, but happens if a monitor is sleeping or extended-but-disabled).

On each monitor, open its on-screen display (OSD) — usually with a button near the power button.
Navigate to Information or Input. The monitor shows which input is active (HDMI 1, DisplayPort, USB-C) and sometimes the source device name.
On Windows: Settings → System → Display → Advanced display. Each monitor has a section showing model name and connection type.
Cross-reference: the monitor showing “HDMI 1” in its OSD matches the Windows Display entry connected via your HDMI 1 cable.
For Thunderbolt / USB-C docks with multiple display outputs, this is the only reliable way to map which dock port = which Windows Display number.

This handles edge cases where Settings’ Identify button doesn’t reach a specific monitor (low-power state, ARC pass-through, etc.).

How to verify the fix worked

Click Identify in Settings. Each monitor briefly shows its number.
Drag the rectangles in Settings to match physical arrangement. Drag your cursor across the boundary between monitors — it should move smoothly in the expected direction.
Run [System.Windows.Forms.Screen]::AllScreens.Count in PowerShell to confirm Windows sees the expected number of monitors.

If none of these work

If the Identify button doesn’t produce a number on one of the monitors, that monitor may be in a special state. Mirror mode: in mirror mode, both monitors show identical content — Identify shows the same number on both. Switch to extend mode via Win + P → Extend. Sleeping or low-power: a monitor that’s in standby may not display the Identify overlay. Press a key to wake it before clicking Identify. USB-C / DisplayLink monitor: third-party DisplayLink adapters sometimes get a different identifier handling. Confirm the DisplayLink driver is current. Hidden monitor: if Windows shows three monitors in Settings but only two are physically connected, an old monitor may be remembered. Disconnect and reconnect cables to force re-enumeration. For consistently confusing monitor numbering, label your physical monitors with stickers (1, 2, 3) matching the Windows numbering after one-time identification.

Bottom line: The Identify button is the right tool — one click overlays the Windows Display number on each physical screen for quick visual mapping.