diff --git a/fuzzers/005-tilegrid/generate.py b/fuzzers/005-tilegrid/generate.py
index 430c26cb..67037f37 100644
--- a/fuzzers/005-tilegrid/generate.py
+++ b/fuzzers/005-tilegrid/generate.py
@@ -17,15 +17,22 @@ def load_tiles(tiles_fn):
             tile_type, tile_name, grid_x, grid_y = record[0:4]
             grid_x, grid_y = int(grid_x), int(grid_y)
             sites = {}
-            for i in range(4, len(record), 2):
-                site_type, site_name = record[i:i + 2]
-                sites[site_name] = site_type
+            clock_region = None
+            if len(record) >= 5:
+                clock_region = record[4]
+                if clock_region == "NA":
+                    clock_region = None
+                for i in range(5, len(record), 2):
+                    site_type, site_name = record[i:i + 2]
+                    sites[site_name] = site_type
+
             tile = {
                 'type': tile_type,
                 'name': tile_name,
                 'grid_x': grid_x,
                 'grid_y': grid_y,
                 'sites': sites,
+                'clock_region': clock_region,
             }
             tiles.append(tile)
 
@@ -59,6 +66,9 @@ def make_database(tiles, pin_func):
             "pin_functions": {},
         }
 
+        if tile["clock_region"]:
+            database[tile["name"]]["clock_region"] = tile["clock_region"]
+
         for site in database[tile["name"]]["sites"]:
             if site in pin_func:
                 database[tile["name"]]["pin_functions"][site] = pin_func[site]
diff --git a/fuzzers/005-tilegrid/generate_tiles.tcl b/fuzzers/005-tilegrid/generate_tiles.tcl
index 6ab62f76..64b62656 100644
--- a/fuzzers/005-tilegrid/generate_tiles.tcl
+++ b/fuzzers/005-tilegrid/generate_tiles.tcl
@@ -14,6 +14,8 @@ proc write_tiles_txt {} {
         set sites [get_sites -quiet -of_objects $tile]
         set typed_sites {}
 
+        set clock_region "NA"
+
         if [llength $sites] {
             set site_types [get_property SITE_TYPE $sites]
             foreach t $site_types s $sites {
@@ -23,10 +25,15 @@ proc write_tiles_txt {} {
                 if [llength $package_pin] {
                     puts $fp_pin "$s [get_property PIN_FUNC $package_pin]"
                 }
+                set clock_region [get_property CLOCK_REGION $s]
             }
         }
+        if {[llength $clock_region] == 0} {
+            set clock_region "NA"
+        }
 
-        puts $fp "$type $tile $grid_x $grid_y $typed_sites"
+
+        puts $fp "$type $tile $grid_x $grid_y $clock_region $typed_sites"
     }
     close $fp_pin
     close $fp
diff --git a/prjxray/grid.py b/prjxray/grid.py
index a751e966..04179e36 100644
--- a/prjxray/grid.py
+++ b/prjxray/grid.py
@@ -1,6 +1,9 @@
 from prjxray import segment_map
-from prjxray.grid_types import BlockType, GridLoc, GridInfo, BitAlias, Bits, BitsInfo
+from prjxray.grid_types import BlockType, GridLoc, GridInfo, BitAlias, Bits, BitsInfo, ClockRegion
 from prjxray.tile_segbits_alias import TileSegbitsAlias
+import re
+
+CLOCK_REGION_RE = re.compile('X([0-9])Y([0-9])')
 
 
 class Grid(object):
@@ -16,6 +19,8 @@ class Grid(object):
         self.loc = {}
         self.tileinfo = {}
 
+        clock_regions = {}
+
         for tile in self.tilegrid:
             tileinfo = self.tilegrid[tile]
             grid_loc = GridLoc(tileinfo['grid_x'], tileinfo['grid_y'])
@@ -46,11 +51,26 @@ class Grid(object):
                         alias=alias,
                     )
 
+            clock_region = None
+            if 'clock_region' in tileinfo:
+                if tileinfo['clock_region'] is not None:
+                    if tileinfo['clock_region'] not in clock_regions:
+                        m = CLOCK_REGION_RE.fullmatch(tileinfo['clock_region'])
+                        assert m is not None, tileinfo['clock_region']
+
+                        clock_regions[tileinfo['clock_region']] = ClockRegion(
+                            name=tileinfo['clock_region'],
+                            x=int(m.group(1)),
+                            y=int(m.group(2)))
+
+                    clock_region = clock_regions[tileinfo['clock_region']]
+
             self.tileinfo[tile] = GridInfo(
                 bits=bits,
                 sites=tileinfo['sites'],
                 tile_type=tileinfo['type'],
                 pin_functions=tileinfo.get('pin_functions', {}),
+                clock_region=clock_region,
             )
 
         x, y = zip(*self.loc.keys())
diff --git a/prjxray/grid_types.py b/prjxray/grid_types.py
index 04c9beb8..a27c3ac8 100644
--- a/prjxray/grid_types.py
+++ b/prjxray/grid_types.py
@@ -11,7 +11,9 @@ class BlockType(enum.Enum):
 
 
 GridLoc = namedtuple('GridLoc', 'grid_x grid_y')
-GridInfo = namedtuple('GridInfo', 'bits sites tile_type pin_functions')
+ClockRegion = namedtuple('ClockRegion', 'name x y')
+GridInfo = namedtuple(
+    'GridInfo', 'bits sites tile_type pin_functions clock_region')
 BitAlias = namedtuple('BitAlias', 'tile_type start_offset sites')
 Bits = namedtuple('Bits', 'base_address frames offset words alias')
 BitsInfo = namedtuple('BitsInfo', 'block_type tile bits')