diff --git a/conf.c b/conf.c
index 682b971..b7c3ddc 100644
--- a/conf.c
+++ b/conf.c
@@ -85,6 +85,7 @@ static char *rtc_file = NULL;
 static double max_update_skew = 1000.0;
 static double correction_time_ratio = 3.0;
 static double max_clock_error = 1.0; /* in ppm */
+static double max_drift = 500000.0; /* in ppm */
 static double max_slew_rate = 1e6 / 12.0; /* in ppm */
 
 static double max_distance = 3.0;
@@ -489,6 +490,8 @@ CNF_ParseLine(const char *filename, int number, char *line)
     parse_double(p, &max_clock_error);
   } else if (!strcasecmp(command, "maxdistance")) {
     parse_double(p, &max_distance);
+  } else if (!strcasecmp(command, "maxdrift")) {
+    parse_double(p, &max_drift);
   } else if (!strcasecmp(command, "maxsamples")) {
     parse_int(p, &max_samples);
   } else if (!strcasecmp(command, "maxslewrate")) {
@@ -1486,6 +1489,14 @@ CNF_GetMaxUpdateSkew(void)
 
 /* ================================================== */
 
+double
+CNF_GetMaxDrift(void)
+{
+  return max_drift;
+}
+
+/* ================================================== */
+
 double
 CNF_GetMaxClockError(void)
 {
diff --git a/conf.h b/conf.h
index b5ac5cf..34c7e41 100644
--- a/conf.h
+++ b/conf.h
@@ -83,6 +83,7 @@ extern char *CNF_GetLeapSecTimezone(void);
 /* Value returned in ppm, as read from file */
 extern double CNF_GetMaxUpdateSkew(void);
 extern double CNF_GetMaxClockError(void);
+extern double CNF_GetMaxDrift(void);
 extern double CNF_GetCorrectionTimeRatio(void);
 extern double CNF_GetMaxSlewRate(void);
 
diff --git a/doc/chrony.conf.adoc b/doc/chrony.conf.adoc
index 55d20ca..bd44b90 100644
--- a/doc/chrony.conf.adoc
+++ b/doc/chrony.conf.adoc
@@ -805,6 +805,16 @@ By default, the maximum error is 1 ppm.
 Typical values for _error-in-ppm_ might be 10 for a low quality clock and 0.1
 for a high quality clock using a temperature compensated crystal oscillator.
 
+[[maxdrift]]*maxdrift* _drift-in-ppm_::
+This directive specifies the maximum assumed drift (frequency error) of the
+system clock. It limits the frequency adjustment that *chronyd* is allowed to
+use to correct the measured drift. It is an additional limit to the maximum
+adjustment that can be set by the system driver (100000 ppm on Linux, 500 ppm
+on FreeBSD and NetBSD, 32500 ppm on Solaris).
++
+By default, the maximum assumed drift is 500000 ppm, i.e. the adjustment is
+limited by the system driver rather than this directive.
+
 [[maxupdateskew]]*maxupdateskew* _skew-in-ppm_::
 One of *chronyd*'s tasks is to work out how fast or slow the computer's clock
 runs relative to its reference sources. In addition, it computes an estimate of
diff --git a/local.c b/local.c
index 848cc3e..2ec173e 100644
--- a/local.c
+++ b/local.c
@@ -42,13 +42,12 @@
 
 /* ================================================== */
 
-/* Maximum allowed frequency offset in ppm, the time must not stop
-   or run backwards */
-#define MAX_FREQ 500000.0
-
 /* Variable to store the current frequency, in ppm */
 static double current_freq_ppm;
 
+/* Maximum allowed frequency, in ppm */
+static double max_freq_ppm;
+
 /* Temperature compensation, in ppm */
 static double temp_comp_ppm;
 
@@ -166,6 +165,11 @@ LCL_Initialise(void)
 
   calculate_sys_precision();
 
+  /* This is the maximum allowed frequency offset in ppm, the time must
+     never stop or run backwards */
+  max_freq_ppm = CNF_GetMaxDrift();
+  max_freq_ppm = CLAMP(0.0, max_freq_ppm, 500000.0);
+
   max_clock_error = CNF_GetMaxClockError() * 1e-6;
 }
 
@@ -406,12 +410,12 @@ LCL_ReadAbsoluteFrequency(void)
 static double
 clamp_freq(double freq)
 {
-  if (freq <= MAX_FREQ && freq >= -MAX_FREQ)
+  if (freq <= max_freq_ppm && freq >= -max_freq_ppm)
     return freq;
 
   LOG(LOGS_WARN, LOGF_Local, "Frequency %.1f ppm exceeds allowed maximum", freq);
 
-  return freq >= MAX_FREQ ? MAX_FREQ : -MAX_FREQ;
+  return CLAMP(-max_freq_ppm, freq, max_freq_ppm);
 }
 
 /* ================================================== */