diff --git a/pandas/_libs/hashtable.pyx b/pandas/_libs/hashtable.pyx
index 9aeb700dd5923..b6b81055f89b2 100644
--- a/pandas/_libs/hashtable.pyx
+++ b/pandas/_libs/hashtable.pyx
@@ -50,12 +50,6 @@ cnp.import_ufunc()
 cdef int64_t iNaT = util.get_nat()
 _SIZE_HINT_LIMIT = (1 << 20) + 7
 
-cdef extern from "datetime.h":
-    bint PyDateTime_Check(object o)
-    void PyDateTime_IMPORT()
-
-PyDateTime_IMPORT
-
 
 cdef size_t _INIT_VEC_CAP = 128
 
diff --git a/pandas/_libs/lib.pyx b/pandas/_libs/lib.pyx
index 503badd0ca8bc..e7e92b7ae987a 100644
--- a/pandas/_libs/lib.pyx
+++ b/pandas/_libs/lib.pyx
@@ -48,7 +48,6 @@ cdef double NAN = nan
 # this is our tseries.pxd
 from datetime cimport (
     get_timedelta64_value, get_datetime64_value,
-    npy_timedelta, npy_datetime,
     PyDateTime_Check, PyDate_Check, PyTime_Check, PyDelta_Check,
     PyDateTime_IMPORT)
 
@@ -62,11 +61,8 @@ from interval import Interval
 
 cdef int64_t NPY_NAT = util.get_nat()
 
-ctypedef unsigned char UChar
-
 cimport util
-from util cimport (is_array, _checknull, _checknan, INT64_MAX,
-                   INT64_MIN, UINT8_MAX)
+from util cimport is_array, _checknull, _checknan
 
 cdef extern from "math.h":
     double sqrt(double x)
diff --git a/pandas/_libs/period.pyx b/pandas/_libs/period.pyx
index 725da22104efc..7760df5144117 100644
--- a/pandas/_libs/period.pyx
+++ b/pandas/_libs/period.pyx
@@ -7,8 +7,7 @@ from cpython cimport (
     PyObject_RichCompareBool,
     Py_EQ, Py_NE)
 
-from numpy cimport (int8_t, int32_t, int64_t, import_array, ndarray,
-                    NPY_INT64, NPY_DATETIME, NPY_TIMEDELTA)
+from numpy cimport int64_t, import_array, ndarray
 import numpy as np
 import_array()
 
@@ -23,12 +22,11 @@ from datetime cimport (
     pandas_datetimestruct,
     pandas_datetimestruct_to_datetime,
     pandas_datetime_to_datetimestruct,
-    PANDAS_FR_ns,
-    INT32_MIN)
+    PANDAS_FR_ns)
 
 
 cimport util
-from util cimport is_period_object, is_string_object
+from util cimport is_period_object, is_string_object, INT32_MIN
 
 from lib cimport is_null_datetimelike
 from pandas._libs import tslib
@@ -90,12 +88,8 @@ cdef extern from "period_helper.h":
                                int microseconds, int picoseconds,
                                int freq) nogil except INT32_MIN
 
-    int64_t get_python_ordinal(int64_t period_ordinal,
-                               int freq) except INT32_MIN
-
     int get_date_info(int64_t ordinal, int freq,
                       date_info *dinfo) nogil except INT32_MIN
-    double getAbsTime(int, int64_t, int64_t)
 
     int pyear(int64_t ordinal, int freq) except INT32_MIN
     int pqyear(int64_t ordinal, int freq) except INT32_MIN
diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index ff20ea287bd9d..745632cf3d719 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -21,7 +21,6 @@ from cpython cimport (
 cdef extern from "Python.h":
     cdef PyTypeObject *Py_TYPE(object)
 
-# this is our datetime.pxd
 from libc.stdlib cimport free
 
 from util cimport (is_integer_object, is_float_object, is_datetime64_object,
@@ -65,11 +64,8 @@ from .tslibs.parsing import parse_datetime_string
 
 cimport cython
 
-import time
-
 from pandas.compat import iteritems, callable
 
-import operator
 import collections
 import warnings
 
@@ -933,10 +929,6 @@ cdef int64_t _NS_UPPER_BOUND = INT64_MAX
 # use the smallest value with a 0 nanosecond unit (0s in last 3 digits)
 cdef int64_t _NS_LOWER_BOUND = -9223372036854775000
 
-cdef pandas_datetimestruct _NS_MIN_DTS, _NS_MAX_DTS
-pandas_datetime_to_datetimestruct(_NS_LOWER_BOUND, PANDAS_FR_ns, &_NS_MIN_DTS)
-pandas_datetime_to_datetimestruct(_NS_UPPER_BOUND, PANDAS_FR_ns, &_NS_MAX_DTS)
-
 # Resolution is in nanoseconds
 Timestamp.min = Timestamp(_NS_LOWER_BOUND)
 Timestamp.max = Timestamp(_NS_UPPER_BOUND)