diff --git a/configure.ac b/configure.ac
index 2638742232..41c12c0a00 100644
--- a/configure.ac
+++ b/configure.ac
@@ -175,12 +175,6 @@ AC_ARG_WITH([natpmp],
             [use_natpmp=$withval],
             [use_natpmp=auto])
 
-AC_ARG_ENABLE([natpmp-default],
-              [AS_HELP_STRING([--enable-natpmp-default],
-                              [if NAT-PMP is enabled, turn it on at startup (default is no)])],
-              [use_natpmp_default=$enableval],
-              [use_natpmp_default=no])
-
 AC_ARG_ENABLE(tests,
     AS_HELP_STRING([--disable-tests],[do not compile tests (default is to compile)]),
     [use_tests=$enableval],
@@ -1793,15 +1787,8 @@ if test "$have_natpmp" = "no"; then
 else
   if test "$use_natpmp" != "no"; then
     AC_MSG_RESULT([yes])
-    AC_MSG_CHECKING([whether to build with NAT-PMP enabled by default])
     use_natpmp=yes
-    natpmp_setting=0
-    if test "$use_natpmp_default" != "no"; then
-      use_natpmp_default=yes
-      natpmp_setting=1
-    fi
-    AC_MSG_RESULT($use_natpmp_default)
-    AC_DEFINE_UNQUOTED([USE_NATPMP], [$natpmp_setting], [NAT-PMP support not compiled if undefined, otherwise value (0 or 1) determines default state])
+    AC_DEFINE([USE_NATPMP], [1], [Define to 1 if UPnP support should be compiled in.])
     if test "$TARGET_OS" = "windows"; then
       NATPMP_CPPFLAGS="$NATPMP_CPPFLAGS -DSTATICLIB -DNATPMP_STATICLIB"
     fi
diff --git a/doc/build-unix.md b/doc/build-unix.md
index 077e278afc..cea8eb919c 100644
--- a/doc/build-unix.md
+++ b/doc/build-unix.md
@@ -72,7 +72,7 @@ executables, which are based on BerkeleyDB 4.8. If you do not care about wallet
 
 To build Bitcoin Core without wallet, see [*Disable-wallet mode*](#disable-wallet-mode)
 
-Optional port mapping libraries (see: `--with-miniupnpc`, `--enable-upnp-default`, and `--with-natpmp`, `--enable-natpmp-default`):
+Optional port mapping libraries (see: `--with-miniupnpc`, `--enable-upnp-default`, and `--with-natpmp`):
 
     sudo apt install libminiupnpc-dev libnatpmp-dev
 
@@ -133,7 +133,7 @@ pass `--with-incompatible-bdb` to configure. Otherwise, you can build Berkeley D
 
 To build Bitcoin Core without wallet, see [*Disable-wallet mode*](#disable-wallet-mode)
 
-Optional port mapping libraries (see: `--with-miniupnpc`, `--enable-upnp-default`, and `--with-natpmp`, `--enable-natpmp-default`):
+Optional port mapping libraries (see: `--with-miniupnpc`, `--enable-upnp-default`, and `--with-natpmp`):
 
     sudo dnf install miniupnpc-devel libnatpmp-devel
 
@@ -187,11 +187,7 @@ libnatpmp
 
 [libnatpmp](https://miniupnp.tuxfamily.org/libnatpmp.html) may be used for NAT-PMP port mapping. It can be downloaded
 from [here](https://miniupnp.tuxfamily.org/files/). NAT-PMP support is compiled in and
-turned off by default. See the configure options for NAT-PMP behavior desired:
-
-    --without-natpmp          No NAT-PMP support, libnatpmp not required
-    --disable-natpmp-default  (the default) NAT-PMP support turned off by default at runtime
-    --enable-natpmp-default   NAT-PMP support turned on by default at runtime
+turned off by default.
 
 Berkeley DB
 -----------