diff --git a/docs/content/DataSource.md b/docs/content/DataSource.md
index 49c583561ba..bfbe1c6b4d9 100644
--- a/docs/content/DataSource.md
+++ b/docs/content/DataSource.md
@@ -1,18 +1,34 @@
 ---
 layout: doc_page
 ---
-A data source is the Druid equivalent of a database table. However, a query can also masquerade as a data source, providing subquery-like functionality. Query data sources are currently only supported by [GroupBy](GroupByQuery.html) queries.
+
+## Datasources
+
+A data source is the Druid equivalent of a database table. However, a query can also masquerade as a data source, providing subquery-like functionality. Query data sources are currently supported only by [GroupBy](GroupByQuery.html) queries.
 
 ### Table Data Source
-The table data source the most common type. It's represented by a string, or by the full structure:
+The table data source is the most common type. It's represented by a string, or by the full structure:
 
 ```json
 {
 	"type": "table",
-	"name": <string_value>
+	"name": "<string_value>"
 }
 ```
 
+### Union Data Source
+This data source unions two or more table data sources.
+
+```json
+{
+       "type": "union",
+       "dataSources": ["<string_value1>", "<string_value2>", "<string_value3>", ... ]
+}
+```
+
+Note that the data sources being unioned should have the same schema.
+
+
 ### Query Data Source
 ```json
 {