diff --git a/src/postgres_history.py b/src/postgres_history.py
index 70d96c8..1bae301 100644
--- a/src/postgres_history.py
+++ b/src/postgres_history.py
@@ -21,8 +21,8 @@ class PostgresHistory:
         end: datetime.datetime,
         limit: int = 2000,
     ) -> List[Dict]:
-        if not 1 <= limit <= 10000:
-            raise ValueError("limit must be between 1 and 10000")
+        if not 1 <= limit <= 100000:
+            raise ValueError("limit must be between 1 and 100000")
         if start >= end:
             raise ValueError("start must be before end")
 
diff --git a/src/web_api.py b/src/web_api.py
index 2e85791..f7764a0 100644
--- a/src/web_api.py
+++ b/src/web_api.py
@@ -452,7 +452,7 @@ async def get_thaiwater_sensors():
 async def get_postgres_history(
     station_code: str,
     hours: int = Query(168, ge=1),
-    limit: int = Query(2000, ge=1, le=10000),
+    limit: int = Query(50000, ge=1, le=100000),
 ):
     """Get historical measurements for a station from PostgreSQL."""
     cache_key = f"{station_code}:{hours}:{limit}"
diff --git a/tests/test_postgres_history.py b/tests/test_postgres_history.py
index 56543ec..50979b8 100644
--- a/tests/test_postgres_history.py
+++ b/tests/test_postgres_history.py
@@ -42,7 +42,7 @@ def test_history_rejects_excessive_limit():
     history = PostgresHistory.__new__(PostgresHistory)
 
     try:
-        history.station_history("P.1", datetime.datetime.now(), datetime.datetime.now(), 10001)
+        history.station_history("P.1", datetime.datetime.now(), datetime.datetime.now(), 100001)
     except ValueError as error:
         assert "limit" in str(error)
     else: