--- a/toolkit/components/telemetry/docs/collection/histograms.rst
+++ b/toolkit/components/telemetry/docs/collection/histograms.rst
@@ -204,16 +204,25 @@ Changing a histogram
 ====================
 Changing histogram declarations after the histogram has been released is tricky. Many tools (like `the aggregator <https://github.com/mozilla/python_mozaggregator>`_) assume histograms don't change. The current recommended procedure is to change the name of the histogram.
 
 * When changing existing histograms, the recommended pattern is to use a versioned name (``PROBE``, ``PROBE_2``, ``PROBE_3``, ...).
 * For enum histograms, it's recommended to set "n_buckets" to a slightly larger value than needed since new elements may be added to the enum in the future.
 
 The one exception is categorical histograms which can only be changed by adding labels, and only until it reaches 50 labels.
 
+Histogram values
+================
+
+The values you can accumulate to Histograms are limited by their internal represenation.
+
+Telemetry Histograms do not record negative values, instead clamping them to 0 before recording.
+
+Telemetry Histograms do not record values greater than 2^31, instead clamping them to INT_MAX before recording.
+
 Adding a JavaScript Probe
 =========================
 
 A Telemetry probe is the code that measures and stores values in a histogram. Probes in privileged JavaScript code can make use of the `nsITelemetry <https://dxr.mozilla.org/mozilla-central/source/toolkit/components/telemetry/nsITelemetry.idl>`_ interface to get references to histogram objects. A new value is recorded in the histogram by calling ``add`` on the histogram object:
 
 .. code-block:: js
 
   let histogram = Services.telemetry.getHistogramById("PLACES_AUTOCOMPLETE_1ST_RESULT_TIME_MS");