diff --git a/cpp/src/arrow/compute/key_map_internal.cc b/cpp/src/arrow/compute/key_map_internal.cc
index b1fc8fb4f8e67..bbaf21ec4e25e 100644
--- a/cpp/src/arrow/compute/key_map_internal.cc
+++ b/cpp/src/arrow/compute/key_map_internal.cc
@@ -258,11 +258,6 @@ uint64_t SwissTable::num_groups_for_resize() const {
   }
 }
 
-uint32_t SwissTable::wrap_global_slot_id(uint32_t global_slot_id) const {
-  uint32_t global_slot_id_mask = static_cast<uint32_t>((1ULL << (log_blocks_ + 3)) - 1);
-  return global_slot_id & global_slot_id_mask;
-}
-
 void SwissTable::early_filter(const int num_keys, const uint32_t* hashes,
                               uint8_t* out_match_bitvector,
                               uint8_t* out_local_slots) const {
@@ -362,7 +357,7 @@ bool SwissTable::find_next_stamp_match(const uint32_t hash, const uint32_t in_sl
   constexpr uint64_t stamp_mask = 0x7f;
   const int stamp =
       static_cast<int>((hash >> bits_shift_for_block_and_stamp_) & stamp_mask);
-  uint32_t start_slot_id = wrap_global_slot_id(in_slot_id);
+  uint32_t start_slot_id = in_slot_id;
   int match_found;
   int local_slot;
   uint8_t* blockbase;
@@ -372,7 +367,7 @@ bool SwissTable::find_next_stamp_match(const uint32_t hash, const uint32_t in_sl
 
     search_block<true>(block, stamp, start_slot_id & 7, &local_slot, &match_found);
 
-    start_slot_id = wrap_global_slot_id(start_slot_id & ~7U + local_slot + match_found);
+    start_slot_id = (start_slot_id & ~7U) + local_slot + match_found;
 
     // Match found can be 1 in two cases:
     // - match was found
diff --git a/cpp/src/arrow/compute/key_map_internal.h b/cpp/src/arrow/compute/key_map_internal.h
index 5ef83b853efe6..3c8b9bf47c983 100644
--- a/cpp/src/arrow/compute/key_map_internal.h
+++ b/cpp/src/arrow/compute/key_map_internal.h
@@ -168,8 +168,6 @@ class ARROW_EXPORT SwissTable {
 
   inline uint64_t num_groups_for_resize() const;
 
-  inline uint32_t wrap_global_slot_id(uint32_t global_slot_id) const;
-
   void init_slot_ids(const int num_keys, const uint16_t* selection,
                      const uint32_t* hashes, const uint8_t* local_slots,
                      const uint8_t* match_bitvector, uint32_t* out_slot_ids) const;
@@ -266,24 +264,6 @@ class ARROW_EXPORT SwissTable {
   MemoryPool* pool_;
 };
 
-// uint32_t SwissTable::extract_group_id(const uint8_t* block_ptr, int slot,
-//                                       uint64_t group_id_mask) const {
-//   // Group id values for all 8 slots in the block are bit-packed and follow the status
-//   // bytes. We assume here that the number of bits is rounded up to 8, 16, 32 or 64. In
-//   // that case we can extract group id using aligned 64-bit word access.
-//   int num_group_id_bits = static_cast<int>(ARROW_POPCOUNT64(group_id_mask));
-//   assert(num_group_id_bits == 8 || num_group_id_bits == 16 || num_group_id_bits == 32
-//   ||
-//          num_group_id_bits == 64);
-
-//   int bit_offset = slot * num_group_id_bits;
-//   const uint64_t* group_id_bytes =
-//       reinterpret_cast<const uint64_t*>(block_ptr) + 1 + (bit_offset >> 6);
-//   uint64_t group_id = (*group_id_bytes >> (bit_offset & 63)) & group_id_mask;
-
-//   return group_id;
-// }
-
 void SwissTable::insert_into_empty_slot(uint32_t slot_id, uint32_t hash,
                                         uint32_t group_id) {
   const int64_t num_groupid_bits = num_groupid_bits_from_log_blocks(log_blocks_);