diff --git a/header.go b/header.go
index 134d7a11..4f3eb53a 100644
--- a/header.go
+++ b/header.go
@@ -21,7 +21,7 @@ type Header[H any] interface {
 	// Hash returns hash of a header.
 	Hash() Hash
 	// Height returns the height of a header.
-	Height() int64
+	Height() uint64
 	// LastHeader returns the hash of last header before this header (aka. previous header hash).
 	LastHeader() Hash
 	// Time returns time when header was created.
diff --git a/headertest/dummy_header.go b/headertest/dummy_header.go
index a654d142..64d21f22 100644
--- a/headertest/dummy_header.go
+++ b/headertest/dummy_header.go
@@ -19,7 +19,7 @@ var ErrDummyVerify = errors.New("dummy verify error")
 type DummyHeader struct {
 	Chainid      string
 	PreviousHash header.Hash
-	HeightI      int64
+	HeightI      uint64
 	Timestamp    time.Time
 
 	hash header.Hash
@@ -34,7 +34,7 @@ func RandDummyHeader(t *testing.T) *DummyHeader {
 
 	dh := &DummyHeader{
 		PreviousHash: RandBytes(32),
-		HeightI:      randInt63(),
+		HeightI:      randUint63(),
 		Timestamp:    time.Now().UTC(),
 	}
 	err := dh.rehash()
@@ -75,7 +75,7 @@ func (d *DummyHeader) rehash() error {
 	return nil
 }
 
-func (d *DummyHeader) Height() int64 {
+func (d *DummyHeader) Height() uint64 {
 	return d.HeightI
 }
 
@@ -128,7 +128,7 @@ func RandBytes(n int) []byte {
 	return buf
 }
 
-func randInt63() int64 {
+func randUint63() uint64 {
 	var buf [8]byte
 
 	_, err := rand.Read(buf[:])
@@ -136,5 +136,5 @@ func randInt63() int64 {
 		return math.MaxInt64
 	}
 
-	return int64(binary.BigEndian.Uint64(buf[:]) & math.MaxInt64)
+	return binary.BigEndian.Uint64(buf[:]) & math.MaxInt64
 }
diff --git a/headertest/store.go b/headertest/store.go
index 690cfc55..d3530804 100644
--- a/headertest/store.go
+++ b/headertest/store.go
@@ -13,8 +13,8 @@ type Generator[H header.Header[H]] interface {
 }
 
 type Store[H header.Header[H]] struct {
-	Headers    map[int64]H
-	HeadHeight int64
+	Headers    map[uint64]H
+	HeadHeight uint64
 }
 
 // NewDummyStore creates a store for DummyHeader.
@@ -25,7 +25,7 @@ func NewDummyStore(t *testing.T) *Store[*DummyHeader] {
 // NewStore creates a generic mock store supporting different type of Headers based on Generator.
 func NewStore[H header.Header[H]](t *testing.T, gen Generator[H], numHeaders int) *Store[H] {
 	store := &Store[H]{
-		Headers:    make(map[int64]H),
+		Headers:    make(map[uint64]H),
 		HeadHeight: 0,
 	}
 
@@ -63,7 +63,7 @@ func (m *Store[H]) Get(ctx context.Context, hash header.Hash) (H, error) {
 }
 
 func (m *Store[H]) GetByHeight(ctx context.Context, height uint64) (H, error) {
-	return m.Headers[int64(height)], nil
+	return m.Headers[height], nil
 }
 
 func (m *Store[H]) GetRangeByHeight(ctx context.Context, from, to uint64) ([]H, error) {
@@ -75,7 +75,7 @@ func (m *Store[H]) GetRangeByHeight(ctx context.Context, from, to uint64) ([]H,
 		return nil, header.ErrNotFound
 	}
 	for i := range headers {
-		headers[i] = m.Headers[int64(from)]
+		headers[i] = m.Headers[from]
 		from++
 	}
 	return headers, nil
@@ -94,7 +94,7 @@ func (m *Store[H]) Has(context.Context, header.Hash) (bool, error) {
 }
 
 func (m *Store[H]) HasAt(_ context.Context, height uint64) bool {
-	return height != 0 && m.HeadHeight >= int64(height)
+	return height != 0 && m.HeadHeight >= height
 }
 
 func (m *Store[H]) Append(ctx context.Context, headers ...H) error {
diff --git a/interface.go b/interface.go
index 1d2d66fb..b7d554ed 100644
--- a/interface.go
+++ b/interface.go
@@ -61,8 +61,8 @@ var (
 
 // ErrNonAdjacent is returned when Store is appended with a header not adjacent to the stored head.
 type ErrNonAdjacent struct {
-	Head      int64
-	Attempted int64
+	Head      uint64
+	Attempted uint64
 }
 
 func (ena *ErrNonAdjacent) Error() string {
diff --git a/metrics.go b/metrics.go
index 51290b6d..81f59f56 100644
--- a/metrics.go
+++ b/metrics.go
@@ -30,7 +30,7 @@ func WithMetrics[H Header[H]](store Store[H]) error {
 				metric.WithAttributes(
 					attribute.String("err", err.Error())))
 		} else {
-			observer.ObserveInt64(headC, head.Height())
+			observer.ObserveInt64(headC, int64(head.Height()))
 		}
 		return nil
 	}
diff --git a/p2p/exchange_test.go b/p2p/exchange_test.go
index ca772d8d..6b81f529 100644
--- a/p2p/exchange_test.go
+++ b/p2p/exchange_test.go
@@ -53,7 +53,7 @@ func TestExchange_RequestHead(t *testing.T) {
 	tests := []struct {
 		requestFromTrusted bool
 		lastHeader         header.Header[*headertest.DummyHeader]
-		expectedHeight     int64
+		expectedHeight     uint64
 		expectedHash       header.Hash
 	}{
 		// routes to trusted peer only
@@ -297,7 +297,7 @@ func Test_bestHead(t *testing.T) {
 	}
 	testCases := []struct {
 		precondition   func() []*headertest.DummyHeader
-		expectedHeight int64
+		expectedHeight uint64
 	}{
 		/*
 			Height -> Amount
diff --git a/p2p/server.go b/p2p/server.go
index 3c3f9f82..b304d2ce 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -175,7 +175,7 @@ func (serv *ExchangeServer[H]) handleRequestByHash(hash []byte) ([]H, error) {
 
 	span.AddEvent("fetched-header-from-store", trace.WithAttributes(
 		attribute.String("hash", header.Hash(hash).String()),
-		attribute.Int64("height", h.Height())),
+		attribute.Int64("height", int64(h.Height()))),
 	)
 	span.SetStatus(codes.Ok, "")
 	return []H{h}, nil
@@ -263,7 +263,7 @@ func (serv *ExchangeServer[H]) handleHeadRequest() ([]H, error) {
 
 	span.AddEvent("fetched-head", trace.WithAttributes(
 		attribute.String("hash", head.Hash().String()),
-		attribute.Int64("height", head.Height())),
+		attribute.Int64("height", int64(head.Height()))),
 	)
 	span.SetStatus(codes.Ok, "")
 	return []H{head}, nil
diff --git a/store/batch.go b/store/batch.go
index 3d41f5fa..7785953f 100644
--- a/store/batch.go
+++ b/store/batch.go
@@ -70,7 +70,7 @@ func (b *batch[H]) getByHeight(height uint64) H {
 		return zero
 	}
 
-	head := uint64(b.headers[ln-1].Height())
+	head := b.headers[ln-1].Height()
 	base := head - ln
 	if height > head || height <= base {
 		return zero
@@ -85,7 +85,7 @@ func (b *batch[H]) Append(headers ...H) {
 	defer b.lk.Unlock()
 	for _, h := range headers {
 		b.headers = append(b.headers, h)
-		b.heights[h.Hash().String()] = uint64(h.Height())
+		b.heights[h.Hash().String()] = h.Height()
 	}
 }
 
diff --git a/store/height_indexer.go b/store/height_indexer.go
index e8f25fe5..7ff8306e 100644
--- a/store/height_indexer.go
+++ b/store/height_indexer.go
@@ -48,7 +48,7 @@ func (hi *heightIndexer[H]) HashByHeight(ctx context.Context, h uint64) (header.
 // IndexTo saves mapping between header Height and Hash to the given batch.
 func (hi *heightIndexer[H]) IndexTo(ctx context.Context, batch datastore.Batch, headers ...H) error {
 	for _, h := range headers {
-		err := batch.Put(ctx, heightKey(uint64(h.Height())), h.Hash())
+		err := batch.Put(ctx, heightKey(h.Height()), h.Hash())
 		if err != nil {
 			return err
 		}
diff --git a/store/heightsub.go b/store/heightsub.go
index b75ef83c..a69f28f6 100644
--- a/store/heightsub.go
+++ b/store/heightsub.go
@@ -82,7 +82,7 @@ func (hs *heightSub[H]) Pub(headers ...H) {
 	}
 
 	height := hs.Height()
-	from, to := uint64(headers[0].Height()), uint64(headers[ln-1].Height())
+	from, to := headers[0].Height(), headers[ln-1].Height()
 	if height+1 != from && height != 0 { // height != 0 is needed to enable init from any height and not only 1
 		log.Fatalf("PLEASE FILE A BUG REPORT: headers given to the heightSub are in the wrong order: expected %d, got %d", height+1, from)
 		return
diff --git a/sync/sync_head.go b/sync/sync_head.go
index 7fa78d0d..8459af27 100644
--- a/sync/sync_head.go
+++ b/sync/sync_head.go
@@ -159,10 +159,10 @@ func (s *Syncer[H]) verify(ctx context.Context, newHead H) (bool, error) {
 		return true, &header.VerifyError{Reason: err, SoftFailure: true}
 	}
 
-	var heightThreshold int64
+	var heightThreshold uint64
 	if s.Params.TrustingPeriod != 0 && s.Params.blockTime != 0 {
 		buffer := time.Hour * 6 / s.Params.blockTime // small buffer to account for network delays
-		heightThreshold = int64(s.Params.TrustingPeriod/s.Params.blockTime + buffer)
+		heightThreshold = uint64(s.Params.TrustingPeriod/s.Params.blockTime + buffer)
 	}
 
 	err = header.Verify(sbjHead, newHead, heightThreshold)
diff --git a/sync/sync_test.go b/sync/sync_test.go
index 02936462..1411c0d0 100644
--- a/sync/sync_test.go
+++ b/sync/sync_test.go
@@ -197,7 +197,7 @@ func TestSyncPendingRangesWithMisses(t *testing.T) {
 
 	lastHead, err := syncer.store.Head(ctx)
 	require.NoError(t, err)
-	require.Equal(t, lastHead.Height(), int64(43))
+	require.Equal(t, lastHead.Height(), uint64(43))
 	exp, err := remoteStore.Head(ctx)
 	require.NoError(t, err)
 
@@ -247,7 +247,7 @@ func TestSyncer_FindHeadersReturnsCorrectRange(t *testing.T) {
 
 	head, err = syncer.store.Head(ctx)
 	require.NoError(t, err)
-	assert.Equal(t, head.Height(), int64(21))
+	assert.Equal(t, head.Height(), uint64(21))
 }
 
 func TestSyncerIncomingDuplicate(t *testing.T) {
diff --git a/verify.go b/verify.go
index 13205858..0c1f3e9e 100644
--- a/verify.go
+++ b/verify.go
@@ -8,14 +8,14 @@ import (
 
 // DefaultHeightThreshold defines default height threshold beyond which headers are rejected
 // NOTE: Compared against subjective head which is guaranteed to be non-expired
-const DefaultHeightThreshold int64 = 80000 // ~ 14 days of 15 second headers
+const DefaultHeightThreshold uint64 = 80000 // ~ 14 days of 15 second headers
 
 // Verify verifies untrusted Header against trusted following general Header checks and
 // custom user-specific checks defined in Header.Verify
 //
 // If heightThreshold is zero, uses DefaultHeightThreshold.
 // Always returns VerifyError.
-func Verify[H Header[H]](trstd, untrstd H, heightThreshold int64) error {
+func Verify[H Header[H]](trstd, untrstd H, heightThreshold uint64) error {
 	// general mandatory verification
 	err := verify[H](trstd, untrstd, heightThreshold)
 	if err != nil {
@@ -45,7 +45,7 @@ func Verify[H Header[H]](trstd, untrstd H, heightThreshold int64) error {
 
 // verify is a little bro of Verify yet performs mandatory Header checks
 // for any Header implementation.
-func verify[H Header[H]](trstd, untrstd H, heightThreshold int64) error {
+func verify[H Header[H]](trstd, untrstd H, heightThreshold uint64) error {
 	if heightThreshold == 0 {
 		heightThreshold = DefaultHeightThreshold
 	}