---
title: clusteringIdentifier
framework: mapkitjs
role: symbol
role_heading: Instance Property
path: mapkitjs/annotation/clusteringidentifier
---

# clusteringIdentifier

An identifier for grouping annotations into the same cluster.

## Declaration

```data
get clusteringIdentifier(): string | null;
set clusteringIdentifier(value: string | null);
```

## Mentioned in

MapKit JS 5

## Discussion

Discussion For MapKit JS to cluster annotations, an annotation needs a clusteringIdentifier. When annotations collide and have the same clusteringIdentifier, MapKit JS clusters them together. The default value is null. For more details, see Clustering annotations.

## See Also

### Managing clustering

- [memberAnnotations](mapkitjs/annotation/memberannotations.md)
- [collisionMode](mapkitjs/annotation/collisionmode-data.property.md)